JP2608351B2 - Semiconductor member and method of manufacturing semiconductor member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor member and a method for manufacturing the semiconductor member. More specifically, the present invention relates to a semiconductor member suitable for an electronic device, an integrated circuit, or a semiconductor member formed on a single crystal semiconductor layer on an insulator or a method for manufacturing the semiconductor member.

[0002]

2. Description of the Related Art The formation of a single-crystal Si semiconductor layer on an insulator is widely known as silicon-on-insulator (SOI) technology and has a number of advantages that cannot be achieved with a bulk Si substrate for fabricating a normal Si integrated circuit. Many researches have been made because devices using SOI technology have the following. That is, by using the SOI technology, Dielectric separation is easy and high integration is possible 1. Excellent radiation resistance 3. 3. Stray capacitance is reduced and high speed is possible. 4. The well process can be omitted. 5. Latch-up can be prevented. Advantages such as the possibility of fully depleted field effect transistor by thinning the film can be obtained.

In order to realize the many advantages in device characteristics as described above, a method for forming an SOI structure has been researched for several decades. The contents are summarized in the following documents, for example.

Special Issue: "Sin
gle-crystal silicon on non
-Single-crystal insulator
s ″; edited by GW Cullen, J.
individual of Crystal Growth,
volume 63, no 3, pp 429-590
(1983). In the old days, SOS (silicon-on-sapphire) is formed by heteroepitaxially forming Si on a single-crystal sapphire substrate by CVD (chemical vapor deposition).
It has been known. Although this was a reasonably successful as the most mature SOI technology, a large number of crystal defects due to the lattice mismatch between the Si layer and the underlying sapphire substrate, the incorporation of aluminum from the sapphire substrate into the Si layer, and above all In addition, the high price of the base and the delay in increasing the area have hindered the spread of its application. In recent years, attempts have been made to realize an SOI structure without using a sapphire substrate. This attempt is roughly divided into the following three.

(1) After the surface of the Si single crystal substrate is oxidized, a window is opened to partially expose the Si substrate, and the portion is used as a seed for laterally epitaxial growth to form a Si single crystal layer on SiO _2. I do. (In this case, SiO ₂
With the deposition of a Si layer on top. (2) Using the Si single crystal substrate itself as an active layer,
SiO ₂ is formed thereunder. (This method does not involve deposition of a Si layer.) (3) Insulation separation is performed after Si is epitaxially grown on a Si single crystal substrate. (This method uses Si
With layer deposition. )

[0006]

As means for achieving the above (1), a method of directly laterally epitaxially growing a single crystal layer Si by CVD, a method of depositing amorphous Si, and performing a heat treatment to solid-phase lateral direction Epitaxial growth method, amorphous or polycrystalline Si layer focused and irradiated with electron beam, laser beam, or other energy beam to grow a single crystal layer on SiO ₂ by melting and recrystallization, and rod heater A method of scanning the melted region in a band shape by using the method (Zone melting recrystallization).
zation) is known. Each of these methods has advantages and disadvantages, but their controllability, productivity, uniformity,
There are still many problems in quality, and none have been industrially put to practical use. For example, the CVD method requires sacrificial oxidation to form a flat thin film, and the solid phase growth method has poor crystallinity. Further, the beam annealing method has problems in processing time by convergent beam scanning, controllability such as beam overlapping and focus adjustment. Of these, Zone Mel
Although the toning recrystallization method is the most mature, and relatively large-scale integrated circuits have been prototyped, many crystal defects such as point defects, line defects, and surface defects (subgrain boundaries) remain. And haven't created a minority carrier device yet.

The method (2) above, in which the Si substrate is not used as seeds for epitaxial growth, includes, for example, the following method.

[0008] 1. An oxide film is formed on a Si single crystal substrate having a V-shaped groove anisotropically etched on its surface, and a polycrystalline Si layer is deposited on the oxide film as thick as the Si substrate.
By polishing from the back surface of the i-base, a single-crystal Si region which is dielectrically separated and surrounded by V-grooves is formed on the thick polycrystalline Si layer. In this method, the crystallinity is good, but the step of depositing polycrystalline Si to a thickness of several hundred microns is called single crystal Si.
There is a problem in terms of controllability and productivity in the step of polishing the substrate from the back surface and leaving only the separated Si active layer.

[0009] 2. SIMOX: Sepa
ratio by ion-implanted o
xygen) is a method of forming a SiO ₂ layer by ion implantation of oxygen into a Si single crystal substrate, and is one of the most mature methods at present because of its good compatibility with the Si process. However, in order to form a SiO ₂ layer, it is necessary to implant oxygen ions at a dose of 10 ¹⁸ ions / cm ² or more, but the implantation time is long and the productivity cannot be said to be high. Cost is high. Furthermore,
Many crystal defects remain, and from an industrial viewpoint, the quality is not sufficient to produce a minority carrier device.

3. A method of forming an SOI structure by dielectric isolation by oxidation of porous Si. This method uses P-type Si
Proton ion implantation of N-type Si layer on the surface of single crystal substrate,
(Imai et al., J. Crystal Growth, Vo.
163, 547 (1983)) or an island formed by epitaxial growth and patterning. From the surface, only the P-type Si substrate is made porous by anodizing in an HF solution so as to surround the Si island. This is a method in which N-type Si islands are dielectrically separated by rapid oxidation. In this method,
The separated Si region is determined before the device process, and there is a problem that the degree of freedom in device design may be limited.

As the method (3) described above, Japanese Patent Laid-Open No. 55-
No. 16464 discloses an N-type single-crystal Si layer formed on a p-type Si wafer, and a glass layer containing an oxide of an N-type impurity provided thereon.
The method has a step of bonding by heat treatment a glass layer containing an oxide of an N-type impurity provided on another silicon wafer. Then, after the bonding step, a P-type S
After the i-wafer is made porous, the porous layer is oxidized, and the porous layer is removed by etching to form an SOI structure.

Japanese Patent Application Publication No. 53-45675 discloses that after a silicon single crystal wafer is made porous, it is oxidized to increase the resistance of the porous layer. It is disclosed that a single crystal Si layer is formed, and a part of the single crystal Si layer is made porous so as to surround the single crystal Si region and the resistance is increased to separate the single crystal Si layer.

Each of the methods described in these publications includes a step of oxidizing the porous layer. Since the porous layer expands due to oxidation, the single crystal Si layer may be affected by strain. However, these methods cannot always form a high-quality single-crystal Si layer on an insulator.

(Object of the Invention) An object of the present invention is to provide a semiconductor member which can meet the above-mentioned problems and the above-mentioned requirements, and a method for producing the member.

Another object of the present invention is to provide a semiconductor member having a single-crystal wafer having excellent crystallinity on an insulator and a single-crystal layer having excellent crystallinity. Another object of the present invention is to provide a method excellent in terms of controllability, controllability and economy.

Still another object of the present invention is to provide a large-scale integrated circuit having an SOI structure even when an expensive SOS or SI
An object of the present invention is to provide a semiconductor member having excellent characteristics that can be substituted for MOX, and a method for economically manufacturing the member in a short time.

[0017]

[0018]

[0019]

[0020]

[0021]

The preferred method of manufacturing a semiconductor member of the present invention is as follows.

The method of manufacturing a semiconductor member of the present invention comprises the steps of preparing a first member having a porous single crystal semiconductor layer and a non-porous single crystal semiconductor layer, the first member and the second member. And a step of attaching the non-porous single crystal semiconductor layer via an insulating layer so as to obtain a multilayer structure in which the non-porous single crystal semiconductor layer is located inside, and a step of removing the porous single crystal semiconductor layer from the multilayer structure. , And.

[0024] Separately, a step of preparing a first member having a porous single crystal semiconductor layer and a non-porous single crystal semiconductor layer includes a step of preparing a second member made of an insulating material and the first member. Bonding a non-porous single-crystal semiconductor layer so that a multilayer structure in which the non-porous single-crystal semiconductor layer is located is obtained, and a step of removing the porous single-crystal semiconductor layer from the multilayer structure. Is characterized by.

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

The semiconductor member of the present invention has a single-crystal semiconductor region having a long carrier lifetime and extremely few defects on an insulator with excellent film thickness uniformity, and is applicable to various semiconductor devices. It is something.
Further, the semiconductor member of the present invention can respond at high speed and can be applied to a highly reliable semiconductor device. Further, the semiconductor member of the present invention is a substitute for expensive SOS or SIMOX.

The method of manufacturing a semiconductor member according to the present invention is excellent in productivity, uniformity, controllability, and economy in obtaining a Si crystal layer having excellent crystallinity on an insulator as much as a single crystal wafer. It provides a method.

Further, according to the method of manufacturing a semiconductor member of the present invention, the advantages of the conventional SOI device can be realized, and a method of manufacturing a semiconductor member that can be applied can be provided.

Further, according to the method of manufacturing a semiconductor member of the present invention, even when a large-scale integrated circuit having an SOI structure is manufactured,
It is possible to provide a method for manufacturing a semiconductor member that can be used as a substitute for expensive SOS or SIMOX.

As described in detail in the embodiments, the method for manufacturing a semiconductor member according to the present invention enables efficient processing in a short time, and is excellent in productivity and economy.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically by taking silicon as an example of a semiconductor material. However, the semiconductor material in the present invention is not limited to silicon at all.

According to observation with a transmission electron microscope, pores having an average diameter of about 600 Å are formed in the porous Si layer, and the density thereof is less than half that of single crystal Si. However, the single crystallinity is maintained. A single crystal is a crystalline solid whose orientation is the same in any part of the sample when attention is paid to any crystal axis, but the porous layer used in the present invention has pores. However, the direction of the crystal axis of the crystalline region is the same in any part, and the crystalline region is a single crystal. Then, it is possible to epitaxially grow a single crystal Si layer on the porous layer. However, at a temperature of 1000 ° C. or higher, rearrangement of atoms located around the inner hole may occur, and the characteristics of the enhanced etching may be impaired. Therefore, in the present invention, S
For the epitaxial growth of the i layer, a molecular beam epitaxial growth method, a plasma CVD method, a low pressure CVD method, a photo CVD method, a bias sputtering method, a liquid phase growth method, or another crystal growth method capable of low temperature growth is preferably used.

The density of the porous layer can be reduced to less than half because a large amount of voids are formed therein. as a result,
Since the surface area per unit volume (specific surface area) is dramatically increased, the chemical etching rate is remarkably increased as compared with the etching rate of a normal non-porous single crystal layer. The present invention maintains the two characteristics of the above-described porous semiconductor, that is, single crystallinity, and allows epitaxial growth of a non-porous semiconductor single crystal on the porous semiconductor substrate, and a non-porous single crystal. It utilizes the fact that the etching rate is remarkably faster than that of a non-porous semiconductor single crystal layer of high quality on a base having an insulating material surface.

The porous layer is made of N-type Si for the following reason.
Formed more easily on the P-type Si layer than on the layer. First, porous Si
Was discovered by Uhlir et al. In the course of research on electropolishing of semiconductors in 1956 (A. Uhlir, Be).
ll Syst. Tech. J. , Vol 35, p.
333 (1956)).

Unagami et al. Studied the dissolution reaction of Si in anodization and reported that the anodic reaction of Si in an HF solution requires holes, and the reaction is as follows ( T. Unami: J. Electrochem. S
oc. , Vol. 127, p. 476 (1980)).

That is, Si + 2HF + (2-n) e ⁺ → SiF ₂ + 2H ⁺ + ne ^- SiF ₂ + 2HF → SiF ₄ + H ₂ SiF ₄ + 2HF → H ₂ SiF ₆ or Si + 4HF + (4-λ) e ⁺ → SiF ₄ + 4H ⁺ + Λe ^- SiF ₄ + 2HF → H ₂ SiF ₆

[0042] Here, e ^+, e ^-, respectively, represent holes and electrons. Also, n and λ are silicon 1 respectively.
It is the number of holes necessary for the atoms to dissolve, and it is said that porous silicon is formed when the condition of n> 2 or λ> 4 is satisfied.

From the above, P-type silicon in which holes are present is more likely to be made porous than N-type silicon having the opposite characteristic. Selectivity in this porosification has been demonstrated by Nagano et al. And Imai (Nagano, Nakajima, Anno, Ohnaka,
Kajiwara; Technical Report of IEICE, vol 79, SS
D 79-9549 (1979), (K. Imai; So
lid-State Electronics Vol
24, 159 (1981)). However, N-type silicon can be made porous depending on the setting of conditions.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Embodiment 1 A method for obtaining a semiconductor substrate by making all the P-type substrate porous and epitaxially growing a single crystal layer will be described.

As shown in FIG. 1A, first, a P-type Si
A single crystal substrate is prepared, and the whole is made porous. The thin film single crystal layer 22 is formed by performing epitaxial growth on the surface of the porous substrate by the crystal growth method capable of low temperature growth.
To form. The P-type Si substrate is made porous by an anodizing method using an HF solution. The porous Si layer 21 has a density of 1.1 to 0.6 g / cm ³ by changing the density of the single crystal Si from 2.33 g / cm ³ to an HF solution concentration of 50 to 20%. Can be changed in the range of

Next, as shown in FIG. 1 (b), another Si substrate 23 is prepared, an oxide layer 24 is formed on the surface thereof, and then the single crystal Si layer 22 on the porous Si substrate 21 is formed.
An Si substrate 23 having the oxide layer 24 on the surface is bonded to the surface. After this, as shown in FIG.
The i substrate 21 is entirely removed by etching to form a thinned single crystal silicon layer 22 on the SiO ₂ layer 24. In the present invention, in order to etch away the porous semiconductor layer without performing an oxidation treatment on the porous semiconductor layer,
Oxidative expansion of the porous semiconductor layer can be prevented, and the influence of strain on the epitaxially grown single crystal layer can be prevented. According to this method, the single-crystal Si layer 22 having a crystallinity equivalent to that of a silicon wafer is flattened and uniformly thinned on the insulating silicon oxide layer 24, and has a large area over the entire wafer. It is formed. The semiconductor substrate thus obtained can be suitably used also in the production of an insulated and separated electronic element.

The layer thickness of the non-porous semiconductor crystal layer formed on the porous semiconductor substrate is preferably 50 μm or less, more preferably 20 μm or less in order to form the semiconductor single crystal layer in the thin film semiconductor device. Is desirable.

Further, the non-porous semiconductor single crystal and the substrate having the surface of the insulating material are attached to each other in an atmosphere of nitrogen, an inert gas or a mixed gas thereof, or in an atmosphere containing an inert gas or nitrogen. It is preferable to carry out in the above, and it is more preferable to carry out in the heated state.

As an etchant for selectively etching the porous semiconductor substrate while leaving the non-porous semiconductor single crystal layer bonded on the substrate having the surface of the insulating material, for example, an aqueous solution of sodium hydroxide, Examples of the etchant include an aqueous solution of potassium hydroxide and a mixed solution of hydrofluoric acid-nitric acid-acetic acid.

Further, the base having an insulating material that can be used in the present invention means that at least the surface of the base is made of an insulating material, or the whole base is made of an insulating material. Good. Examples of a substrate whose surface is made of an insulating material include oxidized surfaces of a single-crystal or polycrystalline silicon substrate, and insulating oxides, nitrides, borides and the like on a conductive or semiconductor substrate surface. One in which a layer of a material is formed can be used. Further, as a specific example of the base body in which the entire base body is made of an insulating material, a base body made of an insulating material such as quartz glass or sintered alumina can be cited.

By the way, in the first embodiment, the example in which the non-porous semiconductor single crystal layer is formed on the porous semiconductor substrate is shown, but the present invention is limited only to the mode of the first embodiment. Instead, the substrate having a single crystal layer made of a material that is difficult to be made porous (eg N-type silicon) and a layer made of a material that is easily made porous (eg P-type silicon) is subjected to a porosification treatment, A porous semiconductor substrate having a non-porous semiconductor single crystal layer may be formed.

Further, in the step of removing the porous semiconductor substrate by etching, during the etching treatment, the porous substrate is not affected by the etchant so that the substrate having the non-porous semiconductor single crystal layer and the surface of the insulating material is not adversely affected. Except for the high quality semiconductor substrate, it may be covered with an etching prevention material.

The thus formed non-porous single crystal layer on the insulator has a carrier lifetime of 5.0 ×.
It can be 10 ⁻⁴ sec or more, and has significantly less crystal defects such as threading dislocations compared to the semiconductor single crystal layer obtained by SIMOX, and the layer thickness distribution of the semiconductor single crystal layer is extremely small. .

Specifically, the dislocation defect density is 2 × 10 ^4.
/ Cm ² or less, and the layer thickness of the semiconductor single crystal layer is 20 cm ^{2 to} 500 cm ² (2
(Inch wafer to 10 inch wafer), the difference between the maximum value and the minimum value of the thickness of the semiconductor single crystal layer can be suppressed to 10% or less of the maximum value of the thickness.

Hereinafter, other embodiments will be described.

Embodiment 2 Hereinafter, Embodiment 2 will be described in detail with reference to FIG.

First, as shown in FIG. 2A, a low impurity concentration layer 122 is formed by epitaxial growth using various thin film growth methods. Alternatively, the P-type Si single crystal substrate 1
N-type single crystal layer 1 by implanting protons on the surface of 21
22 is formed.

Next, as shown in FIG. 2B, a P type S
The i-single-crystal substrate 121 is transformed from the back surface into a porous Si substrate 123 by an anodizing method using an HF solution. This porous Si layer 123 has a density of single crystal Si of 2.33 g.
/ Cm ³ compared to the density of the HF solution concentration 50 to 2
Density 1.1 to 0.6 g / cm ³ by changing to 0%
The range can be changed. This porous layer is formed on the P-type substrate as described above.

As shown in FIG. 2C, another Si
After preparing a substrate 124 and forming an oxide layer 125 on the surface thereof, a single crystal Si layer 122 on a porous Si substrate 123 is formed.
A Si substrate 124 having the oxide layer 125 on the surface is attached to the surface.

After that, the porous Si substrate 123 is wholly etched to leave the thinned single crystal silicon layer 122 on the SiO ₂ layer 125 to form a semiconductor substrate.

According to this method, the oxide layer 1 which is an insulator
25, single crystal Si with crystallinity equivalent to that of silicon wafer
Layer 122 is flattened and uniformly thinned to form a large area throughout the wafer.

The semiconductor substrate thus obtained can be suitably used also in the production of an insulated electronic element.

Embodiment 2 above is an example of a method in which an N-type layer is formed on a P-type substrate before making it porous, and then only the P-type substrate is selectively made porous by anodization. is there.
Also in this embodiment, a semiconductor substrate having a semiconductor single crystal layer having the same performance as that of Embodiment 1 can be obtained.

[Embodiment 3] As shown in FIG. 3A, first, a P-type Si single crystal substrate is prepared, and all of the substrate is made porous. Epitaxial growth is performed on the surface of the porous substrate by various growth methods to form the thin film single crystal layer 12.

As shown in FIG. 3B, another Si
After preparing the substrate 13 and forming the oxide layer 14 on the surface thereof, a Si substrate having the oxide layer 14 on the surface is bonded to the surface of the single crystal Si layer 12 on the porous Si substrate 11.

Next, as shown in FIG. 3B, a Si ₃ N ₄ layer 5 is deposited as an etching prevention film so as to cover the entire bonded two silicon wafers. Next, as shown in FIG. 3C, the Si ₃ N ₄ layer on the surface of the porous silicon substrate is removed. Apiezon wax may be used instead of Si ₃ N ₄ as another etching prevention film material. Thereafter, the porous Si substrate 11 is entirely etched to leave the thinned single-crystal silicon layer 12 on the SiO ₂ layer 14 to form a semiconductor substrate.

FIG. 3C shows a semiconductor substrate obtained by the present invention. That is, by removing the Si ₃ N ₄ layer 15 as the etching prevention film in FIG. 3B, the Si substrate 13 via the SiO ₂ layer 14 which is an insulator is removed.
Single crystal Si layer 2 with crystallinity equivalent to that of a silicon wafer
However, it is formed into a flat and even thin layer and is formed in a large area over the entire wafer. The semiconductor substrate thus obtained can be suitably used from the viewpoint of producing an insulated electronic element. Also in this embodiment example,
A semiconductor substrate having a semiconductor single crystal layer having the same performance as that of the first embodiment can be obtained.

Embodiment 4 Embodiment 4 of the present invention will be described below in detail with reference to FIG.

First, as shown in FIG. 4A, a low impurity concentration layer 112 is formed by epitaxial growth using various thin film growth methods. Alternatively, the P-type Si single crystal substrate 1
11 is ion-implanted with protons to form an N-type single crystal layer 1
12 is formed.

Next, as shown in FIG.
The i-single-crystal substrate 111 is transformed from the back surface into a porous Si substrate 113 by anodization using an HF solution. The porous Si layer 113 has a single crystal Si density of 2.33 g.
/ Cm ³ , the density of the HF solution is 50 to 2
Density 1.1 to 0.6 g / cm ³ by changing to 0%
The range can be changed. This porous layer 113
Are formed on the P-type substrate as described above.

As shown in FIG. 4C, another Si
After preparing a substrate 114 and forming an oxide layer 115 on the surface thereof, a single crystal Si layer 112 on a porous Si substrate 113 is formed.
An Si substrate 114 having an oxide layer 115 on the surface is attached to the surface.

Here, as shown in FIG. 4C, an Si ₃ N ₄ layer 116 is deposited as an etching prevention film 116 so as to cover the entire two bonded silicon wafers. Next, as shown in FIG. 4C, the Si ₃ N ₄ layer on the surface of the porous silicon substrate is removed. Instead of Si ₃ N ₄ as the other etching prevention film 116, a material having excellent etching resistance such as apiezon wax may be used. Thereafter, the porous Si substrate 113 is wholly etched to leave the thinned single crystal silicon layer 112 on the SiO ₂ layer 115 to form a semiconductor substrate. FIG. 4D shows a substrate having a semiconductor layer obtained by the present invention.
That is, the etching prevention film 116 shown in FIG.
By removing the Si ₃ N ₄ layer 116 as a single crystal Si layer 112 having a crystallinity equivalent to that of a silicon wafer is flattened and uniformly thinned on the SiO ₂ layer 115 as an insulator. , Is formed in a large area over the entire wafer.

The semiconductor substrate thus obtained can be suitably used also in the production of electronic elements which are insulated and separated without being adversely affected by the etchant. The semiconductor substrate obtained in this example of the embodiment has the same performance as that of the example 1 of the embodiment.

[Embodiment 5] As shown in FIG. 5A, first, a P-type Si single crystal substrate is prepared, and the whole is made porous. Epitaxial growth is performed on the surface of the porous substrate by various growth methods to form the thin film single crystal layer 32.

As shown in FIG. 5B, another Si
After the base 33 is prepared and the oxide layer 34 is formed on the surface thereof, the Si having the oxide layer 34 on the surface is formed on the surface of the oxide layer 36 formed on the single crystal Si layer 32 on the porous Si base 31.
The base 33 is attached. This bonding step is performed by bringing the cleaned surfaces into close contact with each other and then heating in an inert gas atmosphere or a nitrogen atmosphere. The oxide layer 34 is formed in order to reduce the interface state of the non-porous single crystal layer 32 which is the final active layer.
As shown in FIG. 5B, as the etching prevention film, S
An i ₃ N ₄ layer 35 is deposited to cover the entire two bonded silicon wafers. Next, as shown in FIG. 5C, the Si ₃ N ₄ layer 3 on the surface of the porous silicon substrate 31 is formed.
Remove 5. Si ₃ as another etching prevention film material
Apiezon wax may be used instead of N ₄ . After that, the porous Si substrate 31 is entirely etched to leave the thinned single crystal silicon layer 32 on the SiO ₂ layer to form a semiconductor substrate.

FIG. 5C shows a substrate having a semiconductor layer obtained by the present invention. That is, by removing the Si ₃ N ₄ layer 35 as the etching prevention film shown in FIG. 5B, the crystallinity on the Si substrate 33 is equivalent to that of a silicon wafer through the SiO ₂ layers 34 and 36. Crystal Si
The layer 32 is flattened and uniformly thinned to form a large area over the entire wafer. The semiconductor substrate obtained in this way can also be used favorably in terms of producing an electrically isolated electronic element. The semiconductor substrate obtained in this example of the embodiment has the same performance as that of the example 1 of the embodiment.

Embodiment 6 Embodiment 6 of the present invention will be described below in detail with reference to FIG.

First, as shown in FIG. 6A, a low impurity concentration layer 132 is formed by epitaxial growth by various thin film growth methods. Alternatively, the P-type Si single crystal substrate 1
31 is ion-implanted with protons into the N-type single crystal layer 1
32 is formed.

Next, as shown in FIG.
The i single crystal substrate 131 is transformed from the back surface into a porous Si substrate 133 by an anodization method using an HF solution. This porous Si layer 133 has a single crystal Si density of 2.33 g /
cm ³ , the density of the HF solution is 50 to 20.
%, The density can be changed in the range of 1.1 to 0.6 g / cm ³ . This porous layer is formed on the P-type substrate as described above.

As shown in FIG. 6C, another Si
After preparing the substrate 134 and forming the oxide layer 135 on the surface thereof, the single crystal Si layer 132 on the porous Si substrate 133 is formed.
An Si substrate 134 having the oxide layer 135 is attached to the surface of the oxide layer 137 formed thereon.

Next, as an etching prevention film 136,
An Si ₃ N ₄ layer 136 is deposited over the entire two bonded silicon wafers. Thereafter, as shown in FIG. 6D, Si on the surface of the porous silicon substrate 133 is
The ₃ N ₄ layer 136 is removed. Thereafter, the porous Si substrate 1
31 is chemically etched to form a SiO ₂ layer 135,
A thin film single crystal silicon layer is left on 137 to form a semiconductor substrate.

The semiconductor substrate thus obtained is excellent in the adhesiveness between the layers and can be suitably used from the viewpoint of producing an electronic element which is insulated and separated. The semiconductor substrate obtained in the present embodiment has the same performance as that of the first embodiment.

[Embodiment 7] As shown in FIG. 7 (a), first, a P-type Si single crystal substrate is prepared and the whole is made porous. Epitaxial growth is performed on the surface of the porous substrate by various growth methods to form the thin film single crystal layer 42. As shown in FIG. 7B, another Si substrate 43 is prepared, an oxide layer 44 is formed on the surface thereof, and then an oxide layer formed on the single crystal Si layer 42 on the porous Si substrate 41 is formed. 45, S having the oxide layer 44 on the surface
The i base 43 is attached. This bonding step is performed by bringing the cleaned surfaces into close contact with each other and then heating them in an inert gas atmosphere or a nitrogen atmosphere. The oxide layer 44 is formed in order to reduce the interface state of the single crystal layer 42 which is the final active layer as a semiconductor. As shown in FIG. 7C, the porous Si substrate 41 is wholly etched to leave the thinned single crystal silicon layer on the SiO ₂ layers 44 and 45 to form a semiconductor substrate. FIG. 7C shows a semiconductor substrate obtained by the present invention.

The Si substrate 4 via the SiO ₂ layers 44 and 45
A single-crystal Si layer 42 having a crystallinity equivalent to that of a silicon wafer is formed flat and uniformly thin on 3 and is formed over a large area over the entire wafer. The semiconductor substrate thus obtained can be suitably used from the viewpoint of producing an insulated electronic element. The semiconductor substrate obtained in the present embodiment has the same performance as that of the first embodiment.

Embodiment 8 Embodiment 8 of the present invention will be described below in detail with reference to FIG.

First, as shown in FIG. 8A, a low impurity concentration layer 142 is formed by epitaxial growth by various thin film growth methods. Alternatively, the P-type Si single crystal substrate 1
N-type single crystal layer 1 by ion-implanting protons on the surface of 41
42 is formed.

Next, as shown in FIG. 8B, a P type S
The i-single-crystal substrate 141 is transformed into a porous Si substrate 143 from the back surface by an anodizing method using an HF solution. The porous Si layer 143 has a single crystal Si density of 2.33 g /
Compared with cm ³ , the density of HF solution is 50 to 20
%, The density can be changed in the range of 1.1 to 0.6 g / cm ³ . This porous layer is formed on the P-type substrate 141 as described above.

As shown in FIG. 8C, another Si
After preparing the substrate 144 and forming the oxide layer 145 on the surface thereof, the single crystal Si layer 142 on the porous Si substrate 143 is formed.
The oxide layer 145 is formed on the surface of the oxide layer 146 formed thereon.
Are bonded together.

Thereafter, the porous silicon substrate is entirely chemically etched to leave a thinned single-crystal silicon layer on the SiO ₂ layers 145 and 146 to form a semiconductor substrate.

FIG. 8D shows a semiconductor substrate obtained by the present invention. Si through the SiO ₂ layers 145 and 146
A single-crystal Si layer 142 having a crystallinity equivalent to that of a silicon wafer is formed on the substrate 144 to be flat and thin evenly, and is formed over a large area over the entire wafer.

The semiconductor substrate thus obtained can be suitably used also from the viewpoint of producing an insulated electronic device. The semiconductor substrate obtained in the present embodiment has the same performance as that of the first embodiment.

[Embodiment 9] As shown in FIG. 9 (a), first, a P-type Si single crystal substrate is prepared and all of the substrate is made porous. Epitaxial growth is performed on the surface of the porous substrate 51 by various growth methods to obtain a thin film single crystal layer 5.
Form 2.

As shown in FIG. 9B, a light transmitting substrate 53 typified by glass is prepared, and a porous Si substrate 51 is prepared.
The light transmitting substrate 53 is attached to the surface of the upper single crystal Si layer 52.

Here, as shown in FIG. 9B, an Si ₃ N ₄ layer 54 is deposited as an etching prevention film 54 so as to cover the entire bonded two substrates. Next, FIG.
As shown in (c), S on the surface of the porous silicon substrate
The i ₃ N ₄ layer 54 is removed. After this, the porous Si substrate 5
1 is removed by etching to leave a thinned single-crystal silicon layer 52 on a light-transmitting substrate 53 to form a semiconductor substrate. FIG. 9C shows a semiconductor substrate obtained by the present invention. The semiconductor substrate thus obtained can be suitably used from the viewpoint of manufacturing an electronic element insulated and separated by a light-transmitting insulating material. The semiconductor substrate obtained in the present embodiment has the same performance as that of the first embodiment.

[Embodiment 10] Embodiment 10 of the present invention will be described in detail below with reference to FIG.

First, as shown in FIG. 10A, a low impurity concentration layer 152 is formed by epitaxial growth using various thin film growth methods. Alternatively, the surface of the P-type Si single crystal substrate 151 is ion-implanted with protons to form the N-type single crystal layer 152.

Next, as shown in FIG. 10B, the P-type Si single crystal substrate 151 is transformed from the back surface into a porous Si substrate 153 by anodization using an HF solution.
This porous Si layer 153 has a density of single crystal Si of 2.33 g.
/ Cm ³ compared to the density of the HF solution concentration 50 to 2
Density 1.1 to 0.6 g / cm ³ by changing to 0%
Can be changed in the range of This porous layer 153
Is formed on the P-type substrate 151 as described above.

As shown in FIG. 10C, a light-transmitting substrate 154 is prepared, and a single crystal S on a porous Si substrate 153 is prepared.
The light-transmitting substrate 154 is attached to the surface of the i-layer 152. Then, as shown in FIG. 10C, an Si ₃ N ₄ layer or the like was bonded as an etching prevention
The entire substrate is coated and deposited. Subsequently, FIG.
As shown in (d), the Si ₃ N ₄ layer 155 on the surface of the porous silicon substrate 153 is removed. After this, the porous S
The i-substrate 153 is entirely removed by etching and the light-transmitting substrate 1 is removed.
A thin-film single crystal silicon layer 152 is left on 54 to form a semiconductor substrate.

FIG. 10D shows a semiconductor substrate obtained by the present invention. That is, a single-crystal Si layer 152 having crystallinity equivalent to that of a silicon wafer is formed on a light-transmitting substrate 154.
Flat and uniformly thinned, the entire wafer
It is formed over a large area.

The semiconductor substrate thus obtained can be suitably used from the viewpoint of producing an electronic element insulated and separated by a light-transmitting insulating material. The semiconductor substrate obtained in this example of the embodiment has the same performance as that of the example 1 of the embodiment.

[Embodiment 11] As shown in FIG. 11 (a), first, a P-type Si single crystal substrate is prepared, and the whole is made porous. The thin film single crystal layer 62 is formed by performing epitaxial growth on the surface of the porous substrate 61 by various growth methods.

As shown in FIG. 11B, a light-transmitting substrate 63 typified by glass was prepared, and a porous Si substrate 6 was prepared.
The light-transmitting substrate 63 is attached to the surface of the single crystal Si layer 62 on the substrate 1.

Thereafter, the entirety of the porous Si substrate 61 is etched so that the thinned single-crystal silicon layer 62 is left on the light transmitting substrate 63 to form a semiconductor substrate.

FIG. 11C shows a semiconductor substrate obtained by the present invention. The single crystal Si layer 62 having crystallinity equivalent to that of a silicon wafer is flatly and uniformly thinned on the light transmissive substrate 63 to have a large area over the entire wafer. The semiconductor substrate thus obtained can be suitably used from the viewpoint of producing an electronic element insulated and separated by a light-transmitting insulating material.

[Embodiment 12] Embodiment 12 of the present invention will be described in detail below with reference to FIG.

First, as shown in FIG. 12A, a low impurity concentration layer 162 is formed by epitaxial growth using various thin film growth methods. Alternatively, protons are ion-implanted into the surface of the P-type Si single crystal substrate 161 to form the N-type single crystal layer 162.

Next, as shown in FIG. 12B, the P-type Si single crystal base 161 is transformed from the back surface into a porous Si base 163 by anodization using an HF solution.
This porous Si layer 163 has a single crystal Si density of 2.33 g.
/ Cm ³ , the density of the HF solution is 50 to 2
By changing to 0%, the density is 1.1 to 0.6 g / cm ^3.
Can be changed in the range of This porous layer 163
Is formed on the P-type substrate 163 as described above.

As shown in FIG. 12C, a light-transmitting substrate 164 is prepared, and a single crystal S on a porous Si substrate 163 is prepared.
The light transmissive substrate 164 is attached to the surface of the i layer 162. As shown in FIG. 12C, the porous Si base 163
Is removed by etching to leave the thinned single-crystal silicon layer 162 on the light-transmitting substrate 164 to form a semiconductor substrate.

FIG. 12D shows a semiconductor substrate obtained by the present invention. That is, a single-crystal Si layer 162 having crystallinity equivalent to that of a silicon wafer is formed on a light-transmitting substrate 164.
Flat and uniformly thinned, the entire wafer
It is formed over a large area.

The semiconductor substrate thus obtained can be suitably used from the viewpoint of producing an electronic element insulated and separated by a light-transmitting insulating material. The semiconductor substrate obtained in this example of the embodiment has the same performance as that of the example 1 of the embodiment.

[Embodiment 13] A description will be given with reference to FIG. As shown in FIG. 13A, first, a porous region 1301 is formed in a part of a Si single crystal base 1300. Then, a thin film Si single crystal layer 1302 is formed on the porous region 1301 by various crystal growth methods (FIG. 13B).

The oxide film 13 is formed on the thin silicon single crystal layer 1302.
03 are formed (FIG. 13C).

An oxide film 1305 formed on the surface of another Si substrate 1304 and the oxide film 1303 are bonded together (FIG. 13D).

Next, the Si single crystal gas 1300 that remains without being made porous is removed by mechanical polishing such as grinding, etching, or the like to expose the porous region 1301 (FIG. 1).
3 (e)).

The porous region 1301 is removed by etching.
A semiconductor substrate having a thin-film Si single crystal layer is formed on an insulator (FIG. 13F).

When such a process is adopted, the time required for making the substrate porous can be shortened, and the time for removing the porous Si substrate by etching can also be shortened, so that the efficiency of substrate formation can be improved.

It is also possible to directly bond the thin film Si single crystal layer 1302 and the oxide film 1305 without forming the oxide film 1303 shown in FIG.
Instead of the oxide film 1305 formed thereon, an insulating substrate such as glass can be attached.

It is also possible to incorporate the steps in Embodiments 1 to 12 into this embodiment.

The semiconductor substrate thus obtained has the same excellent performance as the semiconductor substrates obtained in the first to twelfth embodiments.

Hereinafter, the present invention will be described with reference to specific examples.

[0122]

(Example 1) A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns (Si)
The wafer was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And P-type (100) Si with a thickness of 200 microns
The entire substrate was made porous in 24 minutes.

On a P-type (100) porous Si substrate 21, M
BE (Molecular Beam Epitaxy: Molecular Be
The Si epitaxial layer was grown to a thickness of 0.5 μm by the am epitaxy method. The deposition conditions are
It is as follows. Temperature: 700 ° C. Pressure: 1 × 10 ⁻⁹ Torr Growth rate: 0.1 nm / sec

Next, on the surface of this epitaxial layer 21, another Si substrate 23 having a 5000 Å oxide layer 24 formed thereon is placed, and the surface of the Si substrate 23 is set to 800 in a nitrogen atmosphere.
The two Si substrates were firmly bonded together by heating at 0.5 ° C. for 0.5 hour. Then, the porous Si substrate 21 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8).

As described above, the etching rate for a normal Si single crystal hydrofluoric acid / nitric acid solution is about 1 micron per minute (hydrofluoric / nitric acid / acetic acid solution 1: 3: 8).
The etching rate of the porous layer is increased by about 100 times. That is, the porous Si substrate 21 having a thickness of 200 μm was removed in 2 minutes.

[0126] Thus, 0.5μm on the SiO ₂ layer 24
A single-crystal Si layer 22 having a thickness of 2 was formed.

The thickness of the obtained single crystal Si layer was examined by using scanning ellipsometry. Specifically, 3 in
The measurement was performed by scanning the entire surface of the ch wafer. As a result 3
The difference between the maximum value and the minimum value of the thickness of the single-crystal Si layer in the plane of the inch wafer was suppressed to 5% or less of the maximum value of the thickness.

Further, as a result of planar observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained.

Further, MOS ct per single crystal Si layer
When the lifetime of the minority carrier was measured by the method, a high value of 2.0 × 10 ⁻³ sec was shown.

Example 2 A P-type (100) single crystal Si substrate having a diameter of 4 inches and a thickness of 500 μm was used.
Anodization was performed in a 0% HF solution. The current density at this time was 100 mA / cm ² . The porosification rate at this time was 8.4 μm / min. And the total P-type (100) Si substrate with a thickness of 500 microns is 6
It was made porous at 0 minutes.

On the P-type (100) porous Si substrate 21, the Si epitaxial layer 22 was grown at a low temperature of 0.5 micron by the plasma CVD method. The deposition conditions are as follows. Gas: SiH ₄ High frequency power: 100 W Temperature: 800 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 2.5 nm / sec

Next, on the surface of the epitaxial layer 22, another Si layer having a 5000 ° oxide layer 24 formed on the surface is formed.
The bases 23 are superposed and placed in a nitrogen atmosphere at 700.degree.
The two Si substrates were firmly bonded together by heating for 5 hours. Then, a hydrofluoric nitric acid acetic acid solution (1: 3:
8) was used to remove the porous Si substrate 21 by etching.

As described above, the etching rate of a normal Si single crystal to a hydrofluoric-nitric-acetic acid solution is about 1 micron per minute (hydrofluoric-nitric acid-acetic acid solution 1: 3: 8).
The etching rate of the porous layer is increased by about 100 times. That is, the porous Si substrate 21 having a thickness of 500 microns was removed in 5 minutes.

A single-crystal Si layer having a thickness of 0.5 μm was formed on the SiO ₂ layer 24.

Further, the thickness of the obtained single crystal Si layer was examined by using a scanning ellipsometry. Specifically, 4in
The measurement was performed by scanning the entire surface of the ch wafer. Result 4
The difference between the maximum value and the minimum value of the thickness of the single-crystal Si layer in the plane of the inch wafer was suppressed to 7% or less of the maximum value of the thickness.

Further, as a result of the plane observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less, and a new crystal defect was found in the single crystal Si layer forming step. It was not introduced, and it was confirmed that good crystallinity was maintained.

For the single crystal Si layer, MOS ct
When the minority carrier lifetime was measured using the method, a high value of 2.0 × 10 ⁻³ sec was shown.

Example 3 A P-type (100) single crystal Si substrate (S with a diameter of 3 inches and a thickness of 200 μm) (S
(i-wafer) was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . The porosification rate at this time was 8.4 μm / min.
P-type (100) S with a thickness of 200 microns
The entire i-base was made porous in 24 minutes.

The Si epitaxial layer 22 was formed on the P-type (100) porous Si substrate 21 by bias sputtering.
Were grown to a thickness of 0.5 micron. The deposition conditions are as follows. RF frequency: 100 MHz High frequency power: 600 W Temperature: 300 ° C. Ar gas pressure: 8 × 10 ⁻³ Torr Growth time: 60 minutes Target DC bias: −200 V Substrate DC bias: +5 V

Next, on the surface of the epitaxial layer 22, another Si having a 5000 Å oxide layer 24 formed on the surface thereof is formed.
The substrates 23 are superimposed on each other, and are placed at 800 ° C. in a nitrogen atmosphere.
The two Si substrates were firmly bonded together by heating for 5 hours. Then, a hydrofluoric nitric acid acetic acid solution (1: 3:
8) was used to remove the porous Si substrate 21 by etching.

As described above, the etching rate of a normal Si single crystal to a fluorinated nitric acid solution is about 1 micron per minute or less (1: 3: 8 fluorinated nitric acid solution).
The etching rate of the porous layer is increased by about 100 times. That is, the porous Si substrate 21 having a thickness of 200 μm was removed in 2 minutes.

Thus, 0.5 μm is formed on the SiO ₂ layer 24.
It was possible to form a single crystal Si layer having a thickness of.

Example 4 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm
Anodization was performed in a 0% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is 2
It became porous in 4 minutes.

The Si epitaxial layer 22 was grown to a thickness of 0.5 μm on the P-type (100) porous Si substrate 21 by the liquid phase growth method. The growth conditions are as follows. Solvent: Sn Growth temperature: 900 ° C. Growth atmosphere: H ₂ Growth time: 10 minutes

Next, on the surface of this epitaxial layer 22, another Si substrate 23 having a 5000 Å oxide layer 24 formed thereon is placed, and the surface of the Si substrate 23 is set to 800 in a nitrogen atmosphere.
The two Si substrates were firmly bonded together by heating at 0.5 ° C. for 0.5 hour. Then, the porous Si substrate 21 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). Then, the porous Si substrate 21 having a thickness of 200 μm was removed in 2 minutes.

Thus, 0.5 μm is formed on the SiO ₂ layer 24.
A single-crystal Si layer 22 having a thickness of 2 was formed.

Example 5 A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was formed on a silicon substrate.
Anodization was performed in a 0% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is 2
It became porous in 4 minutes.

The Si epitaxial layer 21 was deposited on the P-type (100) porous Si
It was grown to a micron thickness. The deposition conditions are as follows. Source gas: SiH ₄ Carrier gas: H ₂ Temperature: 850 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 3.3 nm / sec

Next, on the surface of this epitaxial layer 22, another Si layer having a 5000 ° oxide layer 24 formed on the surface is formed.
The two Si substrates 23 were firmly bonded by stacking the substrates and heating at 800 ° C. for 0.5 hour in a nitrogen atmosphere. Then, a hydrofluoric nitric acid acetic acid solution (1: 3:
8) was used to remove the porous Si substrate 21 by etching. Then, the porous Si substrate 21 having a thickness of 200 μm was removed in 2 minutes.

Thus, 0.5 μm is formed on the SiO ₂ layer 24.
It was possible to form a single crystal Si layer having a thickness of. When SiH ₂ Cl ₂ was used as the source gas, it was necessary to raise the growth temperature by several tens of degrees, but the enhanced etching characteristic peculiar to the porous substrate was maintained.

Example 6 A Si epitaxial layer 122 having a thickness of 1 micron was grown on a P-type (100) Si substrate 121 having a diameter of 3 inches and a thickness of 200 microns by the CVD method. The deposition conditions are as follows. Reaction gas flow rate: SiH ₄ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 2 min.

This substrate 121 was anodized in a 50% HF solution. Current density at this time is 100m
It was A / cm ² . At this time, the rate of making porous is
8.4 μm / min. The entire P-type (100) Si substrate 121 having a thickness of 200 microns was made porous in 24 minutes. In this anodization, P-type (100) Si
Only the substrate 121 was made porous, and the Si epitaxial layer 122 did not change. Next, another Si substrate 124 on which a 5000 ° oxide layer 125 is formed is superposed on the surface of the epitaxial layer 122, and heated at 800 ° C. for 0.5 hour in a nitrogen atmosphere to form two Si substrates. Were firmly bonded together. Next, the porous Si substrate 123 was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si substrate 123 having a thickness of 200 μm was removed in 2 minutes.

The thickness of the obtained single-crystal Si layer was examined by scanning ellipsometry. The difference between the maximum value and the minimum value of the thickness of the single-crystal Si layer in the plane of the 3-inch wafer was as follows. It was suppressed to 5% or less with respect to the maximum value.

Further, as a result of the plane observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less, and new crystal defects were not formed in the single crystal Si layer forming step. It was not introduced, and it was confirmed that good crystallinity was maintained.

When the lifetime of the minority carrier was measured for the single crystal Si layer by the microwave reflection method, a high value of 2.0 × 10 ⁻³ sec was shown.

(Embodiment 7) CVD is performed on a P-type (100) Si substrate having a diameter of 3 inches and a thickness of 200 μm.
The thickness of the Si epitaxial layer 122 was reduced to 0.5 μm by the method. The deposition conditions are as follows. Reaction gas flow rate: SiH ₄ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 1 min.

This substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . The porosity rate at this time is 8.4 μm /
min. And a P-type (1
00) The entire Si substrate 121 was made porous in 24 minutes. In this anodization, only the P-type (100) Si substrate was made porous, and the Si epitaxial layer 122 did not change. Next, another S layer having a 5000 ° oxide layer 125 formed on the surface of the epitaxial layer 122 was formed.
i substrate 124 is overlaid, and 800 ° C. in a nitrogen atmosphere,
The two Si substrates were firmly bonded together by heating for 0.5 hour. Then, a hydrofluoric-nitric-acetic acid solution (1:
3: 8), the porous Si substrate 123 was removed by etching. Then, the porous Si substrate 123 having a thickness of 200 μm was removed in 2 minutes.

As a result of cross-sectional observation with a transmission electron microscope, S
No new crystal defect was introduced into the i layer 122, and it was confirmed that good crystallinity was maintained.

(Embodiment 8) N-type Si layer 122 is formed by implanting protons into the surface of P-type (100) Si substrate 121 having a diameter of 3 inches and a thickness of 200 microns.
Was formed to a thickness of 1 micron. H ⁺ injection volume is 5 × 1
It was 0 ¹⁵ (ions / cm ² ). 50% on this substrate
Anodization was performed in the HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And a P-type (100) Si substrate 121 having a thickness of 200 microns
It became porous in 24 minutes. As described above, in this anodization, only the P-type (100) Si substrate 121 was made porous, and the N-type Si layer 122 remained unchanged. Next, this N
Oxide layer 1 of 5000 ° on the surface of type Si layer 122
By superposing another Si substrate 124 formed with 25 and heating at 800 ° C. for 0.5 hour in a nitrogen atmosphere,
The two Si substrates were firmly bonded together. Then, using a hydrofluoric nitric acid acetic acid solution (1: 3: 8), the porous Si substrate 1
23 was removed by etching. Then, the porous Si substrate 123 having a thickness of 200 microns was removed in 2 minutes.

As a result of observation of a cross section by a transmission electron microscope,
No new crystal defect was introduced into the i layer 122, and it was confirmed that good crystallinity was maintained.

Example 9 A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was formed on a silicon substrate.
Anodization was performed in a 0% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is 2
It became porous in 4 minutes.

MBE (Molecular Beam Epitaxy: Molecular B) is formed on the P-type (100) porous Si substrate 11.
The Si epitaxial layer 12 was grown to a thickness of 0.5 μm by the electron epitaxy method. The deposition conditions are as follows. Temperature: 700 ° C. Pressure: 1 × 10 ⁻⁹ Torr Growth rate: 0.1 nm / sec

Next, on the surface of this epitaxial layer 12, another Si having an oxide layer 14 of 5000 °
The bases 13 are overlapped and placed in a nitrogen atmosphere at 800.degree.
The two Si substrates were firmly bonded together by heating for 5 hours. Next, Si ₃ N _{4 is formed} by a low pressure CVD method.
The two Si substrates bonded to each other were coated to a thickness of 0.1 μm. Thereafter, only the nitride film on the porous substrate was removed by reactive ion etching. Then, the porous Si substrate 11 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). Then, the porous Si substrate 11 having a thickness of 200 microns was removed in 2 minutes.
After removing the Si ₃ N ₄ layer 15, a substrate having a single-crystal Si layer having a thickness of 0.5 μm was formed on the SiO ₂ layer 14.

As a result of observation of a cross section by a transmission electron microscope,
No new crystal defect was introduced into the i layer, and it was confirmed that good crystallinity was maintained.

Example 10 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

On the P-type (100) porous Si substrate 11, the Si epitaxial layer 12 was grown to a thickness of 0.5 μm by the plasma CVD method. The deposition conditions are as follows. Gas: SiH ₄ High frequency power: 100 W Temperature: 800 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 2.5 nm / sec

Next, on the surface of the epitaxial layer 12, another Si having a 5000 Å oxide layer 14 formed on the surface was formed.
The two Si substrates were firmly bonded together by stacking the substrates and heating them in a nitrogen atmosphere at 800 ° C. for 0.5 hours. Then, two Si substrates bonded with Si ₃ N ₄ were coated with a thickness of 0.1 μm by the low pressure CVD method. Then, only the nitride film on the porous substrate 11 was removed by reactive ion etching. Next, the porous Si substrate 11 was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si substrate 11 having a thickness of 200 microns was removed in 2 minutes.
After removing the Si ₃ N ₄ layer 15, 0.5 on the SiO ₂
A substrate having a single-crystal Si layer 12 having a thickness of μm was formed.

The thickness of the obtained single-crystal Si layer was examined by scanning ellipsometry. The difference between the maximum value and the minimum value of the thickness of the single-crystal Si layer in the plane of the 3-inch wafer was as follows. It was suppressed to 5% or less with respect to the maximum value.

As a result of the observation by the defect revealing etching using the Sirtle etching, the dislocation defect density is 1
It is suppressed to × 10 ³ / cm ² or less, and no new crystal defect is introduced in the single crystal Si layer forming step,
It was confirmed that good crystallinity was maintained.

Further, MOS ct per single crystal Si layer
When the lifetime of the minority carrier was measured by the method, a high value of 2.0 × 10 ⁻³ sec was shown.

(Example 11) Anodization was performed in a 50% HF solution on a P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 200 microns is
It became porous in 24 minutes.

The Si epitaxial layer 12 was formed on the P-type (100) porous Si substrate 11 by bias sputtering.
Were grown to a thickness of 0.5 micron. The deposition conditions are as follows. RF frequency: 100 MHz High frequency power: 600 W Temperature: 300 ° C. Ar gas pressure: 8 × 10 ⁻³ Torr Growth time: 60 minutes Target DC bias: −200 V Substrate DC bias: +5 V

Next, on the surface of the epitaxial layer 12, another Si having an oxide layer 14 of 5000 °
By superimposing the substrates and heating at 800 ° C. for 0.5 hour in a nitrogen atmosphere, the two Si substrates were firmly bonded. Two Si substrates bonded with Si ₃ N ₄ were coated to a thickness of 0.1 μm by low-pressure CVD. Thereafter, only the nitride film on the porous substrate was removed by reactive ion etching. Then, the hydrofluoric / nitric acid solution (1:
3: 8), the porous Si substrate 11 was removed by etching. Then, the porous Si substrate 11 having a thickness of 200 microns was removed in 2 minutes. After removing the Si ₃ N ₄ layer 15, 0.5 μm is formed on the SiO ₂ layer 14.
It was possible to form a substrate having a single crystal Si layer 12 having a thickness of.

The same effect can be obtained by coating apiezon wax instead of the Si ₃ N ₄ layer, and only the porous Si substrate can be completely removed.

Example 12 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was subjected to anodization in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 200 microns is
It became porous in 24 minutes.

The Si epitaxial layer 12 was grown to a thickness of 0.5 micron on the P-type (100) porous Si substrate 11 by the liquid phase growth method. The growth conditions are as follows. Solvent: Sn Growth temperature: 900 ° C. Growth atmosphere: H ₂ growth time: 10 minutes Target DC bias: −200 V Substrate DC bias: +5 V

Next, on the surface of this epitaxial layer 12, another Si having a 5000 Å oxide layer 14 formed on the surface was formed.
The substrates 13 are superimposed on each other, and are placed at 800 ° C. in a nitrogen atmosphere.
The two Si substrates were firmly bonded together by heating for 5 hours. Two Si substrates bonded with Si ₃ N ₄ were coated to a thickness of 0.1 μm by the low pressure CVD method. Then, only the nitride film on the porous substrate was removed by reactive ion etching. Then, the porous Si substrate 11 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). Then, the porous Si substrate 11 having a thickness of 200 microns was removed in 2 minutes. Si
₃ After removal of the N ₄ layer 15 is 0 on the SiO ₂ layer 14.
A substrate having a single-crystal Si layer 12 having a thickness of 5 μm was formed.

The same effect can be obtained when an apiezone wax is used instead of the Si ₃ N ₄ layer, and only the porous Si substrate can be completely removed.

Example 13 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was subjected to anodization in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

The Si epitaxial layer 12 is formed on the P-type (100) porous Si substrate 11 by low-pressure CVD.
It was grown to a micron thickness. The deposition conditions are as follows. Source gas: SiH ₄ Carrier gas: H ₂ Temperature: 850 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 3.3 nm / sec

Next, on the surface of this epitaxial layer 12, another Si having a 5000 Å oxide layer 14 formed on the surface was formed.
The bases 13 are overlapped and placed in a nitrogen atmosphere at 800.degree.
By heating for 5 hours, the two Si substrates were firmly bonded. Next, Si ₃ N _{4 is formed} by a low pressure CVD method.
The two Si substrates bonded to each other were coated with a thickness of 0.1 μm. Thereafter, only the nitride film 15 on the porous substrate 11 was removed by reactive ion etching. Next, the porous Si substrate 11 was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si substrate 11 having a thickness of 200 microns was removed in 2 minutes. After removing the Si ₃ N ₄ layer 15, the SiO ₂
A substrate having a single crystal Si layer having a thickness of 0.5 μm could be formed on the layer 14.

When SiH ₂ Cl ₂ is used as the source gas, it is necessary to raise the growth temperature by several tens of degrees.
The enhanced etching properties typical of porous substrates were maintained.

(Example 14) A Si epitaxial layer 112 was grown to a thickness of 1 micron on a P-type (100) Si substrate 111 having a diameter of 3 inches and a thickness of 200 microns by a CVD method. The deposition conditions are as follows. Reaction gas flow rate: SiH ₄ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 2 min.

This substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . At this time, the porosity rate is 8.4μ.
m / min. And P with a thickness of 200 microns
The entire mold (100) Si substrate was made porous in 24 minutes. In this anodization, only the P-type (100) Si substrate was made porous, and the Si epitaxial layer 122 did not change. Next, on the surface of the epitaxial layer 112, a Si substrate 11 having a 5000 Å oxide layer formed on the surface thereof
The four Si substrates were superposed on each other and overheated in a nitrogen atmosphere at 800 ° C. for 0.5 hour to firmly bond the two Si substrates. Si ₃ N ₄ was bonded by a low pressure CVD method.
One Si substrate was coated with a thickness of 0.1 μm. Then
Only the nitride film on the porous substrate is removed by reactive ion etching. Then, a hydrofluoric nitric acid acetic acid solution (1: 3:
The porous Si substrate 11 was removed by etching using 8). Then, the porous Si substrate 113 having a thickness of 200 μm was removed in 2 minutes.

After removing the Si ₃ N ₄ layer 116, the Si
A substrate having a single-crystal Si layer 112 having a thickness of 1 μm on O ₂ was formed.

The thickness of the obtained single-crystal Si layer was examined by scanning ellipsometry. The difference between the maximum value and the minimum value of the thickness of the single-crystal Si layer in the plane of the 3-inch wafer was as follows. It was suppressed to 5% or less with respect to the maximum value.

Further, as a result of planar observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained.

Further, MOS ct per single crystal Si layer
When the lifetime of the minority carrier was measured by the method, a high value of 2.0 × 10 ⁻³ sec was shown.

(Embodiment 15) A Si epitaxial layer 112 is formed on a P-type (100) Si substrate 111 having a diameter of 3 inches and a thickness of 200 microns by a CVD method.
Grow to a thickness of 5 microns. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 1 min.

This substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
It was m ² . The porosity rate at this time is 8.4 μm /
min. And a P-type (1
00) The entire Si substrate 111 was made porous in 24 minutes. In this anodization, only the P-type (100) Si substrate 11 was made porous, and the Si epitaxial layer 112 did not change.

Next, on the surface of the epitaxial layer 112, a Si substrate 11 having a 5000 Å oxide layer formed on the surface thereof is formed.
4 were overlapped and heated in a nitrogen atmosphere at 800 ° C. for 0.5 hour to firmly bond both Si substrates. Then, Si ₃ N ₄ was coated on the two bonded Si substrates to a thickness of 0.1 μm by the low pressure CVD method. Subsequently, only the nitride film 116 on the porous substrate 113 was removed by reactive ion etching. Then
Porous Si using hydrofluoric nitric acid acetic acid solution (1: 3: 8)
The base 113 was removed by etching. Then, the porous Si substrate 113 having a thickness of 200 microns becomes
Removed in 2 minutes. After removing the Si ₃ N ₄ layer 116, a substrate having a single crystal Si layer 112 having a thickness of 0.5 μm was formed on the SiO ₂ layer 115. As a result of cross-sectional observation with a transmission electron microscope, it was confirmed that new crystal defects were not introduced into the Si layer and good crystallinity was maintained.

(Example 16) N-type Si layer 11 was formed by implanting protons into the surface of P-type (100) Si substrate 111 having a diameter of 3 inches and a thickness of 200 microns.
2 was formed with a thickness of 1 micron. H ⁺ injection volume is 5 ×
It was 10 ¹⁵ (ions / cm ² ). 50
Anodizing was carried out in a HF solution at a concentration of 2.8%. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. The whole P-type (100) Si substrate 111 having a thickness of 200 microns was made porous in 24 minutes. In this anodization, only the P-type (100) Si substrate 111 is made porous, and the N-type S
The i layer 112 did not change. Next, another Si substrate 114 having a 5000 Å oxide layer 115 formed on the surface thereof is superposed on the surface of the N-type Si layer 112, and heated in an oxygen atmosphere at 800 ° C. for 0.5 hour to obtain two layers. S
The i substrate was firmly attached. Next, 0.1 μm was applied to two Si substrates bonded with Si ₃ N ₄ by a low pressure CVD method.
Coated with a thickness of 1 μm. Next, only the nitride film on the porous substrate was removed by reactive ion etching. Next, the porous S
The i substrate 113 was removed by etching. Then, the porous Si substrate 113 having a thickness of 200 microns is formed.
Was removed in 2 minutes. After removing the Si ₃ N ₄ layer 116, a single crystal S having a thickness of 1.0 μm is formed on the SiO _2.
A substrate having the i layer 112 could be formed. As a result of cross-sectional observation with a transmission electron microscope, it was confirmed that new crystal defects were not introduced into the Si layer and good crystallinity was maintained.

(Example 17) A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

On a P-type (100) porous Si substrate 31, M
BE (Molecular Beam Epitaxy: Molecular Be
The Si epitaxial layer 32 was grown to a thickness of 0.5 micron by the am epitaxy method. The deposition conditions are as follows. Temperature: 700 ° C. Pressure: 1 × 10 ⁻⁹ Torr Growth rate: 0.1 nm / sec

Next, an oxide layer 36 having a thickness of 1000 ° was formed on the surface of the epitaxial layer 32. 500 on the surface
Another Si substrate 33 having a 0Å oxide layer 34 formed thereon and the oxide layer 36 are superposed on each other, and the oxide layer 36 is superposed in a nitrogen atmosphere at 800 ° C. at 0.
Both were firmly bonded by heating for 5 hours. Si ₃ N ₄ was bonded by the low pressure CVD method 2
A Si substrate was coated with a thickness of 0.1 μm. Then
Only the nitride film on the porous substrate was removed by reactive ion etching. Then, a hydrofluoric nitric acid acetic acid solution (1: 3:
Using 8), the porous Si substrate 31 was removed by etching. Then, the porous Si substrate 31 having a thickness of 200 microns was removed in 2 minutes. Si ₃ N ₄ layer 3
5 is removed, a thin film single crystal Si layer 3 is formed on SiO _2.
A substrate having No. 2 was formed. As a result of a cross-sectional observation with a transmission electron microscope, no new crystal defects were introduced into the Si layer, and it was confirmed that good crystallinity was maintained.

Example 18 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 200 microns is
It became porous in 24 minutes. The P-type (100) porous Si
The Si epitaxial layer 32 was grown on the base 31 by the plasma CVD method to a thickness of 5 μm. The deposition conditions are as follows. Gas: SiH ₄ High frequency power: 100 W Temperature: 800 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 2.5 nm / sec

Next, an oxide layer 36 having a thickness of 1000Å was formed on the surface of the epitaxial layer 32. After that, another Si substrate 33 having a 5000 Å oxide layer 34 formed on its surface is formed.
And the oxide layer 36 are overlapped with each other, and the mixture is heated in a nitrogen atmosphere
By heating at 0 ° C. for 0.5 hour, both were firmly bonded. Two Si substrates bonded with Si ₃ N ₄ were coated with a thickness of 0.1 μm by the low pressure CVD method. Then, only the nitride film on the porous substrate was removed by reactive ion etching. Next, the porous Si substrate 31 was removed by etching using a KOH solution (6M). Then, porous Si having a thickness of 200 microns is formed.
The substrate 31 was removed in 2 minutes. After removing the Si ₃ N ₄ layer, a single crystal Si having good crystallinity is formed on the SiO _2.
A substrate having the layer 32 was formed.

The thickness of the obtained single-crystal Si layer was examined by scanning ellipsometry. The difference between the maximum value and the minimum value of the thickness of the single-crystal Si layer in the plane of the 3-inch wafer was as follows. Was suppressed to 5% or less with respect to the maximum value.

Further, as a result of planar observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained.

For the single crystal Si layer, MOS ct
When the lifetime of the minority carrier was measured by the method, a high value of 2.0 × 10 ⁻³ sec was shown.

Example 19 A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And 200
The entire P-type (100) Si substrate with a thickness of microns was made porous in 24 minutes. A Si epitaxial layer 32 was grown to a thickness of 1 micron on the P-type (100) porous Si substrate 31 by a bias sputtering method.
The deposition conditions are as follows. RF frequency: 100 MHz High frequency power: 600 W Temperature: 300 ° C. Ar gas pressure: 8 × 10 ⁻³ Torr Growth time: 120 minutes Target DC bias: −200 V Substrate DC bias: +5 V

Next, an oxide layer 36 having a thickness of 1000 ° was formed on the surface of the epitaxial layer 32. Thereafter, another Si substrate 33 having a 5000 ° oxide layer 34 formed on the surface is formed.
And the oxide layer 36 are overlapped with each other, and the mixture is heated in a nitrogen atmosphere
By heating at 0 ° C. for 0.5 hour, both were firmly bonded. Two Si substrates bonded with Si ₃ N ₄ were coated with a thickness of 0.1 μm by the low pressure CVD method. Next, only the nitride film on the porous substrate 31 was removed by reactive ion etching. Next, the porous Si substrate 31 was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si substrate 31 having a thickness of 200 microns was removed in 2 minutes. Si
After removing the ₃ N ₄ layer, a substrate having a single crystal Si layer 32 having crystallinity on SiO ₂ could be formed.

[0203] The same effect can be obtained when the piezo-wax is applied instead of the Si ₃ N ₄ layer 35, and only the porous Si substrate 35 can be completely removed.

Example 20 A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And 200
The entire P-type (100) Si substrate with a thickness of microns was made porous in 24 minutes. On the P-type (100) porous Si substrate 31, a Si epitaxial layer 32 was grown to a thickness of 5 microns by a liquid phase growth method. The growth conditions are as follows. Solvent: Sn Growth temperature: 900 ° C. Growth atmosphere: H ₂ Growth time: 10 minutes

Next, an oxide layer 36 having a thickness of 1000Å was formed on the surface of the epitaxial layer 32. After that, another Si substrate 33 having a 5000 Å oxide layer 34 formed on its surface is formed.
And the oxide layer 36 were brought into close contact with each other and heated at 700 ° C. for 0.5 hour to firmly bond them together. Two sheets of Si ₃ N ₄ bonded together by low pressure CVD
The substrate was coated with a thickness of 0.1 μm. Next, only the nitride film on the porous substrate was removed by reactive ion etching. Then, the porous Si substrate 31 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). Then, porous Si having a thickness of 200 microns is formed.
The substrate 31 was removed in 2 minutes. After removing the Si ₃ N ₄ layer 35, a substrate having a single crystal Si layer 32 on SiO ₂ could be formed. In addition, the same effect was obtained when apiezone wax was used instead of the Si ₃ N ₄ layer, and only the porous Si substrate could be completely removed.

When the thickness of the obtained single crystal Si layer was examined by scanning ellipsometry, the difference between the maximum and minimum values of the thickness of the single crystal Si layer in the plane of the 3-inch wafer was found to be Was suppressed to 5% or less with respect to the maximum value.

As a result of planar observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained.

For the single crystal Si layer, MOS ct
When the lifetime of the minority carrier was measured by the method, a high value of 2.0 × 10 ⁻³ sec was shown.

(Example 21) A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And 200
The entire P-type (100) Si substrate with a thickness of microns was made porous in 24 minutes. P type (100) porous S
The Si epitaxial layer 32 was grown at a low temperature of 1.0 micron on the i substrate 31 by the low pressure CVD method. The deposition conditions are as follows. Source gas: SiH ₄ Carrier gas: H ₂ Temperature: 850 ° C. Pressure: 1 × 10 ^-2 Torr Growth rate: 3.3 nm / sec

Next, an oxide layer 36 having a thickness of 1000Å was formed on the surface of the epitaxial layer 32. After that, another Si substrate 33 having a 5000 Å oxide layer 34 formed on its surface is formed.
And the oxide layer 36 were brought into close contact with each other and heated at 700 ° C. for 0.5 hour to firmly bond them together. The two bonded Si substrates were coated at a thickness of 0.1 μm with Si ₃ N ₄ by low-pressure CVD. Then, only the nitride film 35 on the porous substrate 31 was removed by reactive ion etching. Then, a hydrofluoric nitric acid acetic acid solution (1: 3:
Using 8), the porous Si substrate 31 was removed by etching. Then, the porous Si substrate 31 having a thickness of 200 microns was removed in 2 minutes. Si ₃ N ₄ layer 3
After removing 5, a substrate having a single-crystal Si layer 32 on SiO ₂ was formed.

When SiH ₂ Cl ₂ is used as a source gas, it is necessary to raise the growth temperature by several tens of degrees.
The accelerated etching characteristics unique to the porous substrate were maintained.

(Example 22) A Si epitaxial layer 132 was grown to a thickness of 1 micron by a CVD method on a P-type (100) Si substrate 131 having a diameter of 3 inches and a thickness of 200 micron. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 2 min.

The substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . At this time, the rate of making porous is 8.4.
μm / min. The entire P-type (100) Si substrate 131 having a thickness of 200 μm was made porous in 24 minutes. As described above, in this anodization, P type (1
00) Only the Si substrate 131 was made porous, and the Si epitaxial layer 132 did not change. Next, an oxide layer 137 is formed on the surface of the epitaxial layer 132, another Si substrate 134 having an oxide layer 135 of 5000 Å formed on the surface is superposed on the oxide layer 137, and the oxide layer 137 is placed in a nitrogen atmosphere at 800 ° C. The two Si substrates were firmly bonded together by heating for 5 hours. 0.1 μm on two Si substrates bonded with Si ₃ N ₄ by low pressure CVD
Coated with a thickness of. Thereafter, only the nitride film on the porous substrate was removed by reactive ion etching. Then
The porous Si substrate 133 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). As a result, the porous Si substrate 133 having a thickness of 200 microns becomes 2
Removed in minutes. After removing the Si ₃ N ₄ layer 136,
Single-crystal Si layer 132 having a thickness of 1 μm on SiO ₂
A substrate having

As a result of cross-sectional observation by a transmission electron microscope, S
No new crystal defect was introduced into the i layer, and it was confirmed that good crystallinity was maintained.

(Embodiment 23) A Si epitaxial layer 132 is formed on a P-type (100) Si substrate 131 having a diameter of 4 inches and a thickness of 500 μm by a CVD method.
It was grown to a thickness of 5 microns. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 1 min.

The substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . The porosity rate at this time is 8.4 μm /
min. The entire P-type (100) Si substrate 131 having a thickness of 500 μm was made porous.
In this anodization, only the P-type (100) Si substrate 131 was made porous, and the Si epitaxial layer 132 did not change.

Next, an oxide layer 137 having a thickness of 1000 ° was formed on the surface of the epitaxial layer 132. afterwards,
Another Si substrate 134 having a 5000 ° oxide layer 135 formed on its surface is brought into close contact with the oxide layer 137 at 700 ° C.
By heating for 0.5 hour, both were firmly bonded. Si ₃ N ₄ bonded by low pressure CVD 2
One Si substrate was coated and deposited to a thickness of 0.1 μm, and only the nitride film 136 on the porous substrate 133 was removed by reactive ion etching. Then, a hydrofluoric-nitric-acetic acid solution (1:
3: 8), the porous Si substrate was removed by etching. Then, the porous Si substrate having a thickness of 500 microns was removed in 7 minutes. Si ₃ N ₄ layer 136
After the removal, a substrate having a single-crystal Si layer 132 on SiO ₂ was formed.

The thickness of the obtained single crystal Si layer was examined by scanning ellipsometry, and the difference between the maximum and minimum values of the thickness of the single crystal Si layer in the plane of the 4-inch wafer was found to be Was suppressed to 8% or less of the maximum value.

Further, as a result of planar observation of the single crystal Si layer with a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained.

Further, MOS ct per single crystal Si layer
When the lifetime of the minority carrier was measured by the method, it showed a high value of 2.1 × 10 ⁻³ sec.

(Example 24) The N-type Si layer 13 was formed by ion implantation of protons into the surface of a P-type (100) Si substrate 131 having a diameter of 3 inches and a thickness of 200 microns.
2 was formed with a thickness of 1 micron. H ⁺ injection volume is 5 ×
It was 10 ¹⁵ (ions / cm ² ). 50
Anodizing was carried out in a HF solution at a concentration of 2.8%. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. The entire P-type (100) Si substrate 131 having a thickness of 200 microns was made porous in 24 minutes. In this anodization, only the P-type (100) Si substrate 131 is made porous, and the N-type S
The i layer 132 did not change. Next, on the surface of the epitaxial layer 132, the oxide layer 13 having a thickness of 1000 Å is formed.
7 was formed. After that, 5000 Å oxide layer 13 on the surface
Another Si substrate 134 on which No. 5 was formed and the oxide layer 137 were brought into close contact with each other and heated at 700 ° C. for 0.5 hour to firmly bond the two Si substrates. Reduced pressure CV
Two Si substrates to which Si ₃ N ₄ was adhered were coated by the D method to a thickness of 0.1 μm. Then, only the nitride film on the porous substrate was removed by reactive ion etching. Then, the porous Si substrate 133 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). Then
The porous Si substrate with a thickness of 200 microns was removed in 2 minutes. After removing the Si ₃ N ₄ layer 136, a substrate having the single-crystal Si layer 132 on SiO ₂ was formed. As a result of cross-sectional observation with a transmission electron microscope, S
No new crystal defects were introduced into the i-layer, and it was confirmed that good crystallinity was maintained.

(Example 25) A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was subjected to anodization in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 200 microns is
It became porous in 24 minutes.

On a P-type (100) porous Si substrate 41, M
BE (Molecular Beam Epitaxy: Molecular Be
The Si epitaxial layer 42 was grown to a thickness of 0.5 μm by the am epitaxy method. The deposition conditions are as follows. Temperature: 700 ° C. Pressure: 1 × 10 ⁻⁹ Torr Growth rate: 0.1 nm / sec

Next, an oxide layer 45 having a thickness of 1000Å was formed on the surface of the epitaxial layer 42. Thereafter, another Si base 43 having a 5000 ° oxide layer 44 formed on the surface thereof is formed.
And the oxide layer 45 are overlapped with each other.
By heating at 0 ° C. for 0.5 hour, the two Si substrates were firmly bonded. Then, the porous Si substrate 41 was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). Then, the porous Si substrate 41 having a thickness of 200 microns was removed in 2 minutes.

A base having a thin film single crystal Si layer 42 on SiO ₂ was formed. As a result of cross-sectional observation with a transmission electron microscope, no new crystal defects were introduced in the Si layer,
It was confirmed that good crystallinity was maintained.

Example 26 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes. The P-type (100) porous Si
An Si epitaxial layer 42 was grown on the substrate 41 to a thickness of 5 microns by a plasma CVD method. The deposition conditions are as follows. Gas: SiH ₄ High frequency power: 100 W Temperature: 800 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 2.5 nm / sec

Next, an oxide layer 45 having a thickness of 1000Å was formed on the surface of the epitaxial layer 42. Thereafter, another Si base 43 having a 5000 ° oxide layer 44 formed on the surface thereof is formed.
And the oxide layer 45 are overlapped with each other.
By heating at 0 ° C. for 0.5 hour, the two Si substrates were firmly bonded together. Next, the porous Si substrate 41 was removed by etching using a 6M KOH solution.

As described above, a normal Si single crystal KOH
At 6M, the etch rate for the solution is on the order of less than 1 micron per minute, but the etch rate for the porous layer is increased by a factor of 100. Then, the porous Si substrate having a thickness of 200 microns was removed in 2 minutes.

A single crystal Si layer having good crystallinity was formed on SiO ₂ .

(Example 27) A P-type (100) single crystal Si substrate having a diameter of 5 inches and a thickness of 600 μm was subjected to anodization in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 600 microns is
It became porous in 70 minutes. An Si epitaxial layer 42 was grown to a thickness of 1 micron on a P-type (100) porous Si substrate 41 by a bias sputtering method. The deposition conditions are as follows. RF frequency: 100 MHz High frequency power: 600 W Temperature: 300 ° C. Ar gas pressure: 8 × 10 ⁻³ Torr Growth time: 120 minutes Target DC bias: −200 V Substrate DC bias: +5 V

Next, an oxide layer 45 having a thickness of 1000Å was formed on the surface of the epitaxial layer 42. Thereafter, another Si base 43 having a 5000 ° oxide layer 44 formed on the surface thereof is formed.
Were stacked and heated in a nitrogen atmosphere at 800 ° C. for 0.5 hour to firmly bond the two Si substrates. Next, the porous Si substrate 41 was removed by etching using a hydrofluoric-nitric-acetic acid solution (1: 3: 8). Then 6
Porous Si substrate 4 having a thickness of 00 microns
1 was removed in 7 minutes.

A substrate having a single crystal Si layer 42 having good crystallinity on SiO ₂ could be formed.

When the thickness of the obtained single crystal Si layer was examined by using scanning ellipsometry, the difference between the maximum value and the minimum value of the thickness of the single crystal Si layer in the plane of the 5-inch wafer was found to be Was suppressed to 8% or less of the maximum value.

As a result of the plane observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less, and new crystal defects were not found in the single crystal Si layer forming step. It was not introduced, and it was confirmed that good crystallinity was maintained.

For the single crystal Si layer, MOS ct
When the lifetime of the minority carrier was measured by the method, it showed a high value of 2.1 × 10 ⁻³ sec.

Example 28 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was subjected to anodization in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 200 microns is
It became porous in 24 minutes. The Si epitaxial layer 4 is formed on a P-type (100) porous Si substrate 41 by a liquid phase growth method.
2 was grown to a thickness of 5 microns. The growth conditions are as follows. Solvent: Sn Growth temperature: 900 ° C. Growth atmosphere: H ₂ Growth time: 10 minutes

Next, an oxide layer 45 having a thickness of 1000 ° was formed on the surface of the epitaxial layer. Thereafter, another Si base 43 having a 5000 ° oxide layer 44 formed on the surface thereof is formed.
And heated at 700 ° C. for 0.5 hour to firmly bond the two Si substrates. Next, the porous Si substrate 41 was removed by etching using a hydrofluoric-nitric-acetic acid solution (1: 3: 8). Then, the porous Si substrate 41 having a thickness of 200 microns was removed in 2 minutes.

A substrate having a single crystal Si layer on SiO ₂ could be formed.

(Example 29) A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes. On the P-type (100) porous Si substrate 41, the Si epitaxial layer 42 was grown to a thickness of 0.1 micron by the low pressure CVD method. The deposition conditions are as follows. Source gas: SiH ₄ Carrier gas: H ₂ Temperature: 850 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 3.3 nm / sec

Next, an oxide layer 45 having a thickness of 1000 ° was formed on the surface of the epitaxial layer 42. Thereafter, another Si base 43 having a 5000 ° oxide layer 44 formed on the surface thereof is formed.
Were adhered to each other and heated at 700 ° C. for 0.5 hour to firmly bond the two Si substrates. Next, the porous Si substrate 41 was removed by etching using a hydrofluoric-nitric-acetic acid solution (1: 3: 8). Then, the porous Si substrate 41 having a thickness of 200 microns was removed in 2 minutes.

A substrate having a single crystal Si layer 42 on SiO ₂ was formed. When SiH ₂ Cl ₂ was used as the source gas, it was necessary to raise the growth temperature by several tens of degrees, but the enhanced etching characteristic peculiar to the porous substrate was maintained.

(Example 30) An Si epitaxial layer 142 was grown to a thickness of 1 micron on a P-type (100) Si substrate 141 having a diameter of 3 inches and a thickness of 200 microns by a CVD method. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 2 min.

This substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . At this time, the porosity rate is 8.4μ.
m / min. And the entire P-type (100) Si substrate having a thickness of 200 μm was made porous. In this anodization, only the P-type (100) Si substrate 141 was made porous, and the Si epitaxial layer 142 did not change. Next, on the surface of the epitaxial layer 142, another Si substrate 1 having a 5000 Å oxide layer 145 formed on the surface thereof is formed.
The two Si substrates were firmly bonded together by superposing 44 and heating at 800 ° C. for 0.5 hour in a nitrogen atmosphere. Then, the porous Si substrate was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). Then
The porous Si substrate with a thickness of 200 microns was removed in 2 minutes.

A substrate having a single-crystal Si layer 142 having a thickness of 1 μm was formed on SiO ₂ . As a result of cross-sectional observation with a transmission electron microscope, it was confirmed that new crystal defects were not introduced into the Si layer and good crystallinity was maintained.

(Example 31) A Si epitaxial layer 142 was formed on a P-type (100) Si substrate 141 having a diameter of 3 inches and a thickness of 200 microns by a CVD method.
It was grown to a thickness of 5 microns. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 1 min.

This substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
It was m ² . The porosity rate at this time is 8.4 μm /
min. And a P-type (1
00) The entire Si substrate 141 was made porous in 24 minutes. In this anodization, the P-type (100) Si substrate 141 is used.
Only Si was made porous and there was no change in the Si epitaxial layer 142.

Next, an oxide layer 146 having a thickness of 1000Å was formed on the surface of the epitaxial layer 142. afterwards,
Another Si substrate having a 5000 ° oxide layer 145 formed on the surface thereof was brought into close contact with the substrate and heated at 700 ° C. for 0.5 hour to firmly bond the two Si substrates. Then
The porous Si substrate was removed by etching using a hydrofluoric nitric acid acetic acid solution (1: 3: 8). The 200 micron thick porous Si substrate was then removed in 2 minutes.

A substrate having a single crystal Si layer on SiO ₂ could be formed. As a result of cross-sectional observation with a transmission electron microscope, S
No new crystal defects were introduced into the i-layer, and it was confirmed that good crystallinity was maintained.

(Example 32) The N-type Si layer 14 was formed by ion implantation of protons on the surface of a P-type (100) Si substrate 141 having a diameter of 3 inches and a thickness of 200 microns.
2 was formed to a thickness of 1 micron. H ⁺ injection volume is 5 ×
It was 10 ¹⁵ (ions / cm ² ). 50
% HF solution was anodized. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is 2
It was made porous in 4 minutes. In this anodization, a P-type (10
0) Only the Si substrate 141 is made porous and the N-type Si layer 14 is formed.
No change in 2. Next, this epitaxial layer 1
An oxide layer 146 having a thickness of 1000 ° was formed on the surface of the sample No. 42. Thereafter, another Si substrate having a 5000 Å oxide layer 145 formed on the surface is closely adhered to the oxide layer 146,
By heating at 0 ° C. for 0.5 hour, the two Si substrates were firmly bonded. Next, the porous Si substrate was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si substrate having a thickness of 200 microns was removed in 2 minutes.

A substrate having a single crystal Si layer on SiO ₂ could be formed.

When the thickness of the obtained single crystal Si layer was examined by using scanning ellipsometry, the difference between the maximum value and the minimum value of the thickness of the single crystal Si layer in the plane of the 3-inch wafer was It was suppressed to 5% or less with respect to the maximum value.

Further, as a result of planar observation of the single-crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained.

The MOS ct per single crystal Si layer
When the lifetime of the minority carrier was measured by the method, a high value of 2.2 × 10 ⁻³ sec was shown.

(Example 33) A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was subjected to anodization in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 200 microns is
It became porous in 24 minutes.

On a P-type (100) porous Si substrate 51, M
The Si epitaxial layer 52 was grown at a low temperature of 0.5 micron by the BE method. The deposition conditions are as follows. Temperature: 700 ° C. Pressure: 1 × 10 ⁻⁹ Torr Growth rate: 0.1 nm / sec

Next, the surface of the epitaxial layer 52 is subjected to optical polishing, and fused quartz glass (fused quar) is used.
(rtz glass) The two substrates were firmly bonded by overlapping the substrates and heating at 800 ° C. for 0.5 hour in a nitrogen atmosphere. Si by low pressure CVD
Two substrates with ₃ N ₄ laminated to a thickness of 0.1 μm were coated. Then, only the nitride film 54 on the porous substrate 51 was removed by reactive ion etching. Next, using a hydrofluoric nitric acid acetic acid solution (1: 3: 8), the porous Si substrate 5
1 was removed by etching. Then, the porous Si substrate 51 having a thickness of 200 microns was removed in 2 minutes. After removing the Si ₃ N ₄ layer 54, a substrate having a single crystal Si layer 52 having a thickness of 0.5 μm was formed on a fused glass substrate 53.

As a result of observation of a cross section by a transmission electron microscope,
No new crystal defect was introduced into the i layer, and it was confirmed that good crystallinity was maintained.

Example 34 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate with a thickness of 200 microns is
It became porous in 24 minutes.

An Si epitaxial layer 52 is formed on a P-type (100) porous Si substrate 51 by a plasma CVD method.
It was grown to a micron thickness. The deposition conditions are as follows. Gas: SiH ₄ High frequency power: 100 W Temperature: 800 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 2.5 nm / sec

Next, a glass substrate 53 having a softening point around 500 ° C. which has been optically polished on the surface of the epitaxial layer 52 is overlapped, and the glass substrate 53 is heated at 450 ° C. in a nitrogen atmosphere at 0.5 ° C.
By heating for two hours, the two substrates were firmly bonded together. Two substrates with Si ₃ N ₄ bonded to a thickness of 0.1 μm were coated by the low pressure CVD method. Next, only the nitride film 54 on the porous substrate 51 was removed by reactive ion etching. The porous Si substrate was then etched away using a KOH 6M solution. Then, 20
A porous Si substrate with a thickness of 0 microns is
Removed in 2 minutes. After removing the Si ₃ N ₄ layer, a 5 μm thick single crystal S
The i layer 52 was formed.

Example 35 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

A Si epitaxial layer was grown to a thickness of 1.0 micron on the P-type (100) porous Si substrate 51 by the bias sputter method. The deposition conditions are as follows. RF frequency: 100 MHz High frequency power: 600 W Temperature: 300 ° C. Ar gas pressure: 8 × 10 ⁻³ Torr Growth rate: 120 minutes Target DC bias: −200 V Substrate DC bias: +5 V

Next, a glass substrate 53 having a softening point at about 500 ° C. where the surface of the epitaxial layer 52 has been optically polished is superimposed on the surface thereof at 450 ° C. in a nitrogen atmosphere.
By heating for two hours, the two substrates were firmly bonded together. Two substrates having Si ₃ N ₄ bonded thereto to a thickness of 0.1 μm were coated by a low pressure CVD method. Then, only the nitride film on the porous substrate was removed by reactive ion etching. Thereafter, the porous Si substrate 51 was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, Si made porous with a thickness of 200 microns
The substrate 51 was removed in 2 minutes. After the removal of the Si ₃ N ₄ layer 54, a substrate having a single-crystal Si layer 52 having a thickness of 1.0 μm was formed on the low-melting glass substrate. Further, the same effect can be obtained by coating apiezon wax instead of the Si ₃ N ₄ layer, and only the porous Si substrate 51 can be removed.

When the thickness of the obtained single crystal Si layer was examined by using scanning ellipsometry, the difference between the maximum value and the minimum value of the thickness of the single crystal Si layer in the plane of the 3 inch wafer was found to be It was suppressed to 5% or less of the maximum value.

As a result of planar observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained. When the lifetime of the minority carrier in the single crystal Si layer was measured by the MOS ct method, a high value of 2.0 × 10 ⁻³ sec was shown.

Example 36 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

An Si epitaxial layer was grown to a thickness of 10 μm on a P-type (100) porous Si substrate 51 by a liquid phase growth method. The growth conditions are as follows. Solvent: Sn Growth temperature: 900 ° C Growth atmosphere: H ₂ Growth time: 20 minutes

Next, the surface of the epitaxial layer 52 is optically polished, and a glass substrate 53 having a softening point near 800 ° C. is placed on top of the substrate.
By heating for two hours, the two substrates were firmly bonded. Si ₃ N ₄ 0.1 μm by low pressure CVD method
The two substrates, which were laminated to each other with a thickness of 1 mm, were coated. Thereafter, only the nitride film on the porous substrate was removed by reactive ion etching. Next, hydrofluoric / nitric acid solution (1: 3: 8)
Was used to remove the porous Si substrate by etching. Then, Si made porous with a thickness of 200 microns
The substrate 51 was removed in 2 minutes. After the removal of the Si ₃ N ₄ layer 54, a substrate having a single-crystal Si layer 52 having a thickness of 10 μm was formed on the glass substrate 53. Also,
The same effect was obtained when apiezone wax was used instead of the Si ₃ N ₄ layer, and only the porous Si substrate could be completely removed.

(Example 37) A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

An Si epitaxial layer 52 is formed on a P-type (100) porous Si substrate 51 by a low pressure CVD method.
It was grown to a thickness of microns. The deposition conditions are as follows. Source gas: SiH ₄ 800 SCCM Carrier gas: H ₂ 150 l / min. Temperature: 850 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 3.3 nm / sec

Next, a fused quartz glass substrate 53 which has been optically polished is superposed on the surface of the epitaxial layer 52 and heated in a nitrogen atmosphere at 800 ° C. for 0.5 hour, whereby the two substrates are firmly bonded. Stuck together.

[0272] Si ₃ N ₄ is 0.1 μm thick by a low pressure CVD method.
The two substrates deposited and adhered to each other with a thickness of m were coated. Thereafter, only the nitride film on the porous substrate was removed by reactive ion etching. Next, the porous Si substrate 51 was removed by etching using a hydrofluoric / nitric acid / acetic acid solution. Then, a porous S having a thickness of 200 microns is formed.
The i-substrate was removed in 2 minutes. After removing the Si ₃ N ₄ layer, a substrate having a single-crystal Si layer 52 having a thickness of 1.0 μm was formed on the quartz glass substrate 53. When SiH ₂ Cl ₂ was used as the source gas, the growth temperature had to be raised by several tens of degrees, but the accelerated etching characteristic peculiar to the porous substrate was maintained.

(Example 38) A Si epitaxial layer 152 was grown to a thickness of 1 micron on a P-type (100) Si substrate 151 having a diameter of 4 inches and a thickness of 300 microns by CVD. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 2 min.

This substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . Also, the porosity rate at this time is 8.4 μm.
m / min. And P with a thickness of 300 microns
The entire mold (100) Si substrate 151 was made porous in 36 minutes. As described above, in this anodization, the P-type (10
0) Only the Si substrate 151 was made porous, and the Si epitaxial layer 152 did not change. Next, an optically polished fused silica glass substrate 154 is superposed on the surface of the epitaxial layer 152, and the surface is
By heating at 0.5 ° C. for 0.5 hour, the two substrates were firmly bonded. Si ₃ N ₄ was reduced to 0.
The two substrates were deposited at a thickness of 1 μm and bonded together. Then, the nitride film 155 on the porous substrate 153 is formed.
Only those were removed by reactive ion etching. Next, the porous Si is added using a hydrofluoric / nitric acid solution (1: 3: 8).
The substrate was etched away. Then, the porous Si substrate 153 having a thickness of 300 microns was removed in 4 minutes. After removing the Si ₃ N ₄ layer 155, a 1 μm-thick single-crystal Si
A substrate having the layer 152 was formed. As a result of a cross-sectional observation with a transmission electron microscope, no new crystal defects were introduced into the Si layer, and it was confirmed that good crystallinity was maintained.

(Embodiment 39) An Si epitaxial layer 152 is formed on a P-type (100) Si substrate 151 having a diameter of 3 inches and a thickness of 200 microns by CVD.
Grow to a thickness of 5 microns. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 1 min.

The substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . The porosity rate at this time is 8.4 μm /
min. And a P-type (1
00) The entire Si substrate 151 was made porous in 24 minutes. In this anodization, only the P-type (100) Si substrate was made porous, and the Si epitaxial layer 152 did not change.

Next, a fused quartz glass substrate 154 that has been optically polished is superposed on the surface of the epitaxial layer 152, and heated at 800 ° C. for 0.5 hour in a nitrogen atmosphere, whereby the two substrates are firmly bonded. Stuck together. Decompression C
Si ₃ N ₄ was deposited to a thickness of 0.1 μm by the VD method, and the two bonded substrates were covered. Thereafter, only the nitride film 155 on the porous substrate 153 was removed by reactive ion etching. Next, the porous Si substrate was etched away using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si substrate 153 having a thickness of 200 microns was removed in 2 minutes. Si ₃
After removing the N ₄ layer 155, a substrate having a single-crystal Si layer 152 having a thickness of 0.5 μm was formed on the glass substrate 154. As a result of a cross-sectional observation with a transmission electron microscope, no new crystal defects were introduced into the Si layer, and it was confirmed that good crystallinity was maintained.

(Example 40) An N-type Si layer 15 was formed by ion implantation of protons on the surface of a P-type (100) Si substrate 151 having a diameter of 4 inches and a thickness of 300 microns.
2 was formed with a thickness of 1 micron. H ⁺ injection volume is 5 ×
It was 10 ¹⁵ (ions / cm ² ). 50
Anodizing was carried out in a HF solution at a concentration of 2.8%. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. The whole P-type (100) Si substrate 151 having a thickness of 300 microns was made porous in 37 minutes. In this anodization, only the P-type (100) Si substrate is made porous, and the N-type Si layer 1
52 had no change. Next, the N-type Si layer 152
The two substrates were firmly bonded by superposing a fused silica glass substrate 154 having its surface optically polished and heating at 800 ° C. for 0.5 hour in a nitrogen atmosphere.

[0279] Si ₃ N ₄ is 0.1 μm thick by a low pressure CVD method.
The two substrates which were deposited to a thickness of m and bonded together were covered. Next, only the nitride film 155 on the porous substrate 153 was removed by reactive ion etching. Next, the porous Si substrate was removed by etching using a hydrofluoric-nitric-acetic acid solution. Then, the porous Si substrate 151 having a thickness of 300 microns was removed in 4 minutes. Si ₃ N ₄
After removing the layer 155, 1.
A substrate having a single-crystal Si layer 152 having a thickness of 0 μm was formed.

The thickness of the obtained single-crystal Si layer was examined by scanning ellipsometry. The difference between the maximum value and the minimum value of the single-crystal Si layer in the plane of the 4-inch wafer was as follows. It was suppressed to 6% or less of the maximum value.

Further, as a result of planar observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained. In addition, when the lifetime of the minority carrier of the single crystal Si layer was measured by using the MOS ct method, a high value of 2.2 × 10 ⁻³ sec was shown.

That is, according to the present invention, it is possible to obtain a Si crystal layer having excellent crystallinity on a light-transmitting insulating substrate represented by glass as well as a single-crystal wafer, thereby improving productivity, uniformity, and the like. A method for forming a semiconductor substrate excellent in controllability and economy can be provided. Further according to the invention,
The advantages of the conventional SOI device can be utilized, and a method for forming a semiconductor substrate having a wide range of applications can be provided.

(Example 41) A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

On a P-type (100) porous Si substrate 61, M
The Si epitaxial layer 62 was grown to a thickness of 0.5 μm by the BE method. The deposition conditions are as follows. Temperature: 700 ° C. Pressure: 1 × 10 ⁻⁹ Torr Growth rate: 0.1 nm / sec

Next, a fused quartz glass substrate 63 that has been optically polished is superposed on the surface of the epitaxial layer 62, and heated at 800 ° C. for 0.5 hour in a nitrogen atmosphere, whereby the two substrates are firmly bonded. Stuck together. Then
The porous Si substrate 61 was removed by etching using a hydrofluoric / nitric acid / acetic acid solution. Then, the porous Si substrate 61 having a thickness of 200 microns was removed in 2 minutes. A substrate having a single-crystal Si layer 62 having a thickness of 0.5 μm was formed on the quartz glass substrate 63. As a result of a cross-sectional observation with a transmission electron microscope, no new crystal defects were introduced into the Si layer, and it was confirmed that good crystallinity was maintained.

Example 42 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes. An Si epitaxial layer 62 was grown on a P-type (100) porous Si substrate 61 to a thickness of 5 μm by a plasma CVD method. The deposition conditions are as follows. Gas: SiH ₄ High frequency power: 100 W Temperature: 800 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 2.5 nm / sec

Next, the surface of the epitaxial layer 62 is optically polished, and a glass substrate having a softening point in the vicinity of 500 ° C. is placed on top of the substrate, and heated at 450 ° C. for 0.5 hour in a nitrogen atmosphere. The substrate was firmly bonded. Then KOH. Using a 6M solution, the porous Si substrate 61 was removed by etching. Then, the porous Si substrate 61 having a thickness of 200 microns was removed in 2 minutes. A base having a single-crystal Si layer 62 having a thickness of 5 μm was formed on the low softening point glass base 63.

Example 43 A P-type (100) single crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

An Si epitaxial layer 62 is formed on a P-type (100) porous Si substrate 61 by bias sputtering.
Was grown to a thickness of 1.0 micron. The deposition conditions are as follows. RF frequency: 100 MHz High frequency power: 600 W Temperature: 300 ° C. Ar gas pressure: 8 × 10 ⁻³ Torr Growth rate: 120 minutes Target DC bias: −200 V Substrate DC bias: +5 V

Next, the surface of the epitaxial layer 62 is optically polished, and a glass substrate 63 having a softening point near 500 ° C. is placed on the surface thereof.
By heating for two hours, the two substrates were firmly bonded. Next, the porous Si substrate 61 was removed by etching using a NaOH 7M solution.

As described above, 7M of ordinary Si single crystal
The etch rate for NaOH solutions is on the order of less than 1 micron per minute, but the etch rate for the porous layer is increased by a factor of 100. That is, the porous Si substrate 61 having a thickness of 200 microns was removed in 2 minutes. A base having a single-crystal Si layer 62 having a thickness of 1.0 μm was formed on the low-melting glass base 63.

The thickness of the obtained single-crystal Si layer was examined by scanning ellipsometry. The difference between the maximum value and the minimum value of the single-crystal Si layer in the plane of the 3-inch wafer was as follows. It was suppressed to 5% or less of the maximum value.

Further, as a result of planar observation of the single crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained. When the lifetime of the minority carrier of the single crystal Si layer was measured by using the MOS ct method, it showed a high value of 2.1 × 10 ⁻³ sec.

Example 44 A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 μm was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

A Si epitaxial layer 62 was grown on a P-type (100) porous Si substrate 61 to a thickness of 10 μm by a liquid phase growth method. The growth conditions are as follows. Solvent: Sn Growth temperature: 900 ° C Growth atmosphere: H ₂ Growth time: 20 minutes

Next, a glass substrate 63 having a softening point at about 800 ° C. where the surface of the epitaxial layer 62 has been optically polished is superimposed, and is placed in a nitrogen atmosphere at 750 ° C. and 0.5 ° C.
By heating for two hours, the two substrates were firmly bonded. Next, the porous Si substrate 61 was removed by etching using a hydrofluoric / nitric acid / acetic acid solution. Then, the porous Si substrate 61 having a thickness of 200 microns was removed in 2 minutes. A base having a single-crystal Si layer 62 having a thickness of 10 μm was formed on a glass base 63.

(Example 45) A P-type (100) single-crystal Si substrate having a diameter of 3 inches and a thickness of 200 microns was anodized in a 50% HF solution. The current density at this time was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / min. And the entire P-type (100) Si substrate having a thickness of 200 microns is
It became porous in 24 minutes.

An Si epitaxial layer 52 is formed on a P-type (100) porous Si substrate 61 by a low pressure CVD method.
It was grown to a micron thickness. The deposition conditions are as follows. Source gas: SiH ₄ 800 SCCM Carrier gas: H ₂ 150 l / min. Temperature: 850 ° C. Pressure: 1 × 10 ⁻² Torr Growth rate: 3.3 nm / sec

Next, a fused quartz glass substrate 63 that has been optically polished is superposed on the surface of the epitaxial layer 62, and heated at 800 ° C. for 0.5 hour in a nitrogen atmosphere, so that the two substrates are firmly bonded. Stuck together. Then
The porous Si substrate 61 was removed by etching using a hydrofluoric / nitric acid / acetic acid solution. Then, the porous Si substrate 61 having a thickness of 200 microns was removed in 2 minutes. A substrate having a single-crystal Si layer 62 having a thickness of 1.0 μm was formed on the quartz glass substrate 63. When SiH ₂ Cl ₂ was used as the source gas, the growth temperature had to be raised by several tens of degrees, but the accelerated etching characteristic peculiar to the porous substrate was maintained.

(Example 46) An Si epitaxial layer 162 was grown to a thickness of 1 micron on a P-type (100) Si substrate 161 having a diameter of 4 inches and a thickness of 300 microns by CVD. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 2 min.

The substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . Also, the porosity rate at this time is 8.4 μm.
The entire P-type (100) Si substrate 161 having a thickness of 300 μm at m / min was made porous in 37 minutes. In this anodization, a P-type (100) Si substrate 16
Only 1 was made porous, and the Si epitaxial layer 162 did not change. Next, a fused quartz glass substrate 164 that had been optically polished was superposed on the surface of the epitaxial layer, and heated at 800 ° C. for 0.5 hour in a nitrogen atmosphere, whereby the two substrates were firmly bonded. Next, the porous Si substrate 163 was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si substrate 163 having a thickness of 300 microns becomes 4
Removed in minutes. A base having a single-crystal Si layer 162 having a thickness of 1 μm was formed on the quartz glass base 164.

The thickness of the obtained single crystal Si layer was examined by scanning ellipsometry. The difference between the maximum value and the minimum value of the thickness of the single crystal Si layer in the plane of the 4-inch wafer was as follows. It was suppressed to 7% or less of the maximum value.

Further, as a result of planar observation of the single crystal Si layer with a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained. When the minority carrier lifetime of the single crystal Si layer was measured by the MOS ct method, a high value of 2.0 × 10 ⁻³ sec was obtained.

Example 47 A Si epitaxial layer 162 was formed on a P-type (100) Si substrate 161 having a diameter of 3 inches and a thickness of 200 microns by CVD.
It was grown to a thickness of 5 microns. The deposition conditions are as follows. Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 l / min. Temperature: 1080 ° C. Pressure: 80 Torr Time: 1 min.

This substrate was anodized in a 50% HF solution. The current density at this time is 100 mA / c
m ² . The porosity rate at this time is 8.4 μm /
min and a P-type (10
0) The entire Si substrate 161 was made porous in 24 minutes.
In this anodization, only the P-type (100) Si substrate 161 was made porous, and the Si epitaxial layer 162 did not change. Next, a fused quartz glass substrate 164 having been subjected to optical polishing is superposed on the surface of the epitaxial layer 162 and heated at 800 ° C. for 0.5 hour in a nitrogen atmosphere, whereby the two substrates were firmly bonded to each other. . Next, the porous Si substrate 163 was removed by etching using a hydrofluoric / nitric acid / acetic acid solution. Then, the porous Si substrate having a thickness of 200 microns was removed in 2 minutes. A single-crystal Si layer having a thickness of 0.5 μm was formed on the glass substrate. As a result of cross-sectional observation with a transmission electron microscope,
No new crystal defects were introduced in the layer, and it was confirmed that good crystallinity was maintained.

(Example 48) An N-type Si layer 1 was formed by ion implantation of protons on the surface of a P-type (100) Si substrate 161 having a diameter of 3 inches and a thickness of 200 microns.
62 was formed to a thickness of 1 micron. H ⁺ injection volume is 5
× 10 ¹⁵ (ions / cm ² ). 5
Anodization was performed in a 0% HF solution. The current density at this time was 100 mA / cm ² . The porosification rate at this time was 8.4 μm / min, and the entire P-type (100) Si substrate 161 having a thickness of 200 μm was made porous in 24 minutes. In this anodization, only the P-type (100) Si substrate 161 is made porous and the N-type Si
Layer 162 did not change. Next, a fused quartz glass substrate 164 that has been optically polished is superposed on the surface of the epitaxial layer 162, and is placed at 800 ° C. and 0.8 ° C. in a nitrogen atmosphere.
By heating for 5 hours, the two substrates were firmly bonded. Next, the porous Si substrate 163 was removed by etching using a hydrofluoric / nitric acid solution (1: 3: 8). Then, the porous Si having a thickness of 200 microns is formed.
Substrate 163 was removed in 2 minutes. A single-crystal Si layer 162 having a thickness of 1.0 μm was formed on the glass substrate 164. As a result of a cross-sectional observation with a transmission electron microscope, no new crystal defects were introduced into the Si layer, and it was confirmed that good crystallinity was maintained.

Example 49 A P-type (100) single-crystal Si substrate having a diameter of 6 inches and a thickness of 600 microns was anodized in a 50% HF solution. The current density at this time was 10 mA / cm ² . A porous layer having a thickness of 20 microns was formed on the surface in 10 minutes. Low pressure CVD on the P-type ((100) porous Si substrate)
By the method, a Si epitaxial layer was grown to a thickness of 0.5 μm. The deposition conditions are as follows. Gas: SiH ₂ Cl ₂ (0.6 l / min), H ₂ (1
00 l / min) Temperature: 850 ° C. Pressure: 50 Torr Growth rate: 0.1 μm / min.

Next, the surface of this epitaxial layer is
nm. 0.8 μm on the thermal oxide film thus obtained.
Another silicon substrate having a micron oxide layer on its surface was overlaid and heated in a nitrogen atmosphere at 900 ° C. for 1.5 hours to firmly bond the two substrates.

Then, 5 minutes from the back side of the silicon substrate
80 micron grinding and polishing was performed to expose the porous layer.

[0310] Si ₃ N ₄ was reduced to 0.
The two substrates were deposited to a thickness of 1 μm and bonded together. Next, only the nitride film on the porous substrate was removed by reactive ion etching.

Thereafter, the bonded substrates were selectively etched using a hydrofluoric / nitric acid / acetic acid solution. After 15 minutes, only the single crystal Si layer remains without being etched, and the single crystal Si layer remains.
As an etch stop material, the porous Si layer was selectively etched and completely removed.

[0312] The etching rate of the non-porous Si single crystal with respect to the etching solution was extremely low, even after 15 minutes.
Å, the selectivity with the etching rate of the porous layer was very large, and the etching amount in the non-porous Si layer was practically negligible. After the removal of the Si ₃ N ₄ layer, 0.5 μm
A single-crystal Si layer having a thickness of μm was formed.

The same effect was obtained when apiesone wax or electron wax was applied instead of the Si ₃ N ₄ layer, and only the porous Si layer could be completely removed.

When the thickness of the obtained single-crystal Si layer was examined by scanning ellipsometry, the difference between the maximum value and the minimum value of the thickness of the single-crystal Si layer in the plane of the 6-inch wafer was as follows. It was suppressed to 10% or less of the maximum value.

Further, as a result of planar observation of the single-crystal Si layer by a transmission electron microscope, the dislocation defect density was suppressed to 1 × 10 ³ / cm ² or less. It was not introduced, and it was confirmed that good crystallinity was maintained. When the minority carrier lifetime of the single crystal Si layer was measured by the MOS ct method, a high value of 2.0 × 10 ⁻³ sec was obtained.

[0316]

As described in detail above, the semiconductor member of the present invention has a single crystal semiconductor region having a large carrier lifetime and extremely few defects on an insulator with excellent film thickness uniformity. Can be applied to various semiconductor devices. Further, the semiconductor member of the present invention can be applied to a semiconductor device capable of high-speed response and having high reliability. In addition, the semiconductor member of the present invention uses expensive SOS or SI.
It is an alternative to MOX.

The method for manufacturing a semiconductor member according to the present invention is superior in productivity, uniformity, controllability, and economy in obtaining a Si crystal layer having excellent crystallinity on an insulator as much as a single crystal wafer. It is to provide a method.

Further, according to the method for manufacturing a semiconductor member of the present invention, the advantages of the conventional SOI device can be realized, and a method for manufacturing a semiconductor member that can be applied can be provided.

According to the method of manufacturing a semiconductor member of the present invention, a large-scale integrated circuit having an SOI structure can be manufactured.
It is possible to provide a method for manufacturing a semiconductor member that can be used as a substitute for expensive SOS or SIMOX.

As described in detail in the embodiments, the method for manufacturing a semiconductor member according to the present invention enables efficient processing in a short time, and is excellent in productivity and economy.

[Brief description of the drawings]

FIG. 1 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 2 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 3 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 4 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 5 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 6 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member according to the present invention.

FIG. 7 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 8 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 9 is a schematic view schematically showing one example of the steps of the method for manufacturing a semiconductor member of the present invention.

FIG. 10 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 11 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member according to the present invention.

FIG. 12 is a schematic view schematically showing one example of steps of a method for manufacturing a semiconductor member of the present invention.

FIG. 13 is a schematic view schematically showing one example of the steps of the method for manufacturing a semiconductor member of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 21/316 H01L 21/306 B 21/762 21/76 D

Claims (49)

(57) [Claims] 1. A step of preparing a first member having a porous single-crystal semiconductor layer and a non-porous single-crystal semiconductor layer, and connecting the first member and the second member with an insulating layer interposed therebetween. Bonding the non-porous single-crystal semiconductor layer so that a multilayer structure located inside is obtained, and removing the porous single-crystal semiconductor layer from the multi-layer structure. Semiconductor member manufacturing method. 2. The method according to claim 1, wherein the porous single-crystal semiconductor layer and the non-porous single-crystal semiconductor layer are made of silicon. 3. The method according to claim 2, wherein the porous single-crystal semiconductor layer is a P-type. 4. A non-porous single-crystal semiconductor layer having a thickness of 5
The method for manufacturing a semiconductor member according to claim 1, wherein the diameter is 0 μm or less. 5. The method according to claim 1, wherein the bonding step is performed in an atmosphere containing nitrogen. 6. The method for manufacturing a semiconductor member according to claim 1, wherein said bonding step includes a heat treatment. 7. The method according to claim 1, wherein the non-porous single-crystal semiconductor layer is formed by epitaxial growth. 8. The non-porous single crystal semiconductor layer is formed by a molecular beam epitaxy method, a plasma CVD method, a low pressure CVD method,
The method for manufacturing a semiconductor member according to claim 1, wherein the semiconductor member is formed by a method selected from a photo CVD method, a liquid phase growth method, and a sputtering method. 9. The method for manufacturing a semiconductor member according to claim 1, wherein the porous single crystal semiconductor layer is obtained by making a nonporous single crystal semiconductor porous by anodizing. 10. The method according to claim 9, wherein the anodization is performed in an HF solution. 11. The method according to claim 2, wherein the non-porous single-crystal semiconductor layer is neutral or N-type. 12. The N-type silicon is formed by proton irradiation or epitaxial growth.
3. The method for manufacturing a semiconductor member according to item 1. 13. The method according to claim 1, wherein the second member comprises a silicon substrate. 14. The method according to claim 1, wherein the second member and the insulating layer are formed by oxidizing a surface of a silicon substrate. 15. The first member and the insulating layer are formed by oxidizing a surface of the non-porous single-crystal silicon layer of a substrate having a porous single-crystal silicon layer and a non-porous single-crystal silicon layer. The method for manufacturing a semiconductor member according to claim 1, wherein the semiconductor member is formed. 16. The method according to claim 16, wherein the insulating layer comprises a first insulating layer and a second insulating layer.
Wherein the first member and the first insulating layer form a surface of the non-porous single-crystal silicon layer of a substrate having a porous single-crystal silicon layer and a non-porous single-crystal silicon layer. 2. The method according to claim 1, wherein the second member and the second insulating layer are formed by oxidizing, and the second member and the second insulating layer are formed by oxidizing a surface of a silicon substrate. 17. The method of claim 14, wherein the oxidation is a thermal oxidation.
17. The method for manufacturing a semiconductor member according to any one of Items 1 to 16. 18. The method of removing a porous single crystal semiconductor layer,
2. The method for manufacturing a semiconductor member according to claim 1, wherein the method is performed by etching. 19. The method according to claim 18, wherein an aqueous solution is used as an etchant for the etching. 20. The method according to claim 19, wherein the etchant contains hydrofluoric acid. 21. The first member, after the non-porous single-crystal semiconductor is made porous to form the porous single-crystal semiconductor layer, the non-porous semiconductor layer is formed on the porous single-crystal semiconductor layer. 21. The method of manufacturing a semiconductor member according to claim 1, wherein the method is performed by forming a semiconductor device. 22. The first member, comprising: forming a second single crystal semiconductor layer of a second conductivity type on a first single crystal semiconductor layer of a first conductivity type; 21. The method for manufacturing a semiconductor member according to claim 1, wherein the single crystal semiconductor layer is made porous. 23. The first member, wherein the non-porous single-crystal semiconductor layer is formed on the porous single-crystal semiconductor layer obtained by partially making the non-porous single-crystal semiconductor porous. 4. The method according to claim 1, further comprising: after the bonding step, a step of removing a region of the non-porous single-crystal semiconductor that remains without being made porous, and a step of removing the porous single-crystal semiconductor layer. 20. The method for manufacturing a semiconductor member according to 20. 24. The method for manufacturing a semiconductor member according to claim 23, wherein the region of the non-porous single-crystal semiconductor remaining without being made porous is removed by mechanical removal. 25. The method according to claim 24, wherein the mechanical removal is performed by a method selected from grinding and polishing. 26. A step of preparing a first member having a porous single-crystal semiconductor layer and a non-porous single-crystal semiconductor layer, wherein a second member made of an insulating material and the first member are separated from each other. ,
Bonding the non-porous single-crystal semiconductor layer to obtain a multilayer structure located inside, and removing the porous single-crystal semiconductor layer from the multilayer structure, Semiconductor member manufacturing method. 27. The porous single-crystal semiconductor layer and the non-porous single-crystal semiconductor layer are made of silicon.
3. The method for manufacturing a semiconductor member according to item 1. 28. The method according to claim 27, wherein the porous single-crystal semiconductor layer is of a P-type. 29. The method according to claim 26, wherein the thickness of the non-porous single-crystal semiconductor layer is 50 μm or less. 30. The method according to claim 26, wherein the bonding step is performed in an atmosphere containing nitrogen. 31. The method for manufacturing a semiconductor member according to claim 26, wherein the bonding step includes a heat treatment. 32. The method according to claim 26, wherein the non-porous single-crystal semiconductor layer is formed by epitaxial growth. 33. The non-porous single crystal semiconductor layer is formed by a molecular beam epitaxy method, a plasma CVD method, or a low pressure CVD method.
27. The method of manufacturing a semiconductor member according to claim 26, wherein the method is performed by a method selected from a group consisting of a method selected from the group consisting of a method, a photo-CVD method, a liquid phase growth method, and a sputtering method. 34. The method of manufacturing a semiconductor member according to claim 26, wherein the porous single crystal semiconductor layer is obtained by making a nonporous single crystal semiconductor porous by anodization. 35. The method according to claim 34, wherein the anodization is performed in an HF solution. 36. The method according to claim 27, wherein the non-porous single-crystal semiconductor layer is neutral or N-type. 37. The N-type silicon is formed by proton irradiation or epitaxial growth.
3. The method for manufacturing a semiconductor member according to item 1. 38. The method according to claim 26, wherein the second member made of an insulating material is a light-transmitting member. 39. The method according to claim 38, wherein the light transmitting member is made of glass. 40. The method according to claim 39, wherein the glass is quartz glass. 41. The removing of the porous single-crystal semiconductor layer comprises:
The method of manufacturing a semiconductor member according to claim 26, wherein the method is performed by etching. 42. The method according to claim 41, wherein an aqueous solution is used as an etchant for the etching. 43. The method according to claim 42, wherein the etchant contains hydrofluoric acid. 44. The first member, after the non-porous single-crystal semiconductor is made porous to form the porous single-crystal semiconductor layer, the non-porous semiconductor layer is formed on the porous single-crystal semiconductor layer. 44. The method of manufacturing a semiconductor member according to claim 26, wherein the semiconductor member is formed by forming the following. 45. The first member, comprising: forming a second single-crystal semiconductor layer of second conductivity type on a first single-crystal semiconductor layer of first conductivity type; 44. The method for manufacturing a semiconductor member according to claim 26, wherein the single crystal semiconductor layer is made porous. 46. The first member, wherein the non-porous single-crystal semiconductor layer is formed on the porous single-crystal semiconductor layer obtained by partially making the non-porous single-crystal semiconductor porous. 27. The method according to claim 26, further comprising, after the bonding step, a step of removing a region of the non-porous single-crystal semiconductor that remains without being made porous and a step of removing the porous single-crystal semiconductor layer. 44. The method for manufacturing a semiconductor member according to 43. 47. The method of manufacturing a semiconductor member according to claim 46, wherein the removal of the region of the non-porous single crystal semiconductor which remains without being made porous is performed by mechanical removal. 48. The method according to claim 47, wherein the mechanical removal is performed by a method selected from grinding and polishing. 49. A semiconductor member manufactured by the method according to any one of claims 1 to 48.