JP3098811B2 - Insulated gate field effect transistor and semiconductor device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated gate field effect transistor and a semiconductor device using the same, and more particularly to an insulated gate field effect transistor having an insulated gate field effect transistor formed on an insulator substrate. The present invention relates to a semiconductor device using the same.

[0002]

2. Description of the Related Art The formation of a single-crystal Si semiconductor layer on an insulator is widely known as a silicon-on-insulator (SOI) technique, and involves a number of things that cannot be achieved with a bulk Si substrate for fabricating a normal Si integrated circuit. Much research has been done on the advantages of devices utilizing SOI technology. In other words, by using SOI technology,
. Dielectric separation is easy and high integration is possible. Excellent radiation resistance. The stray capacitance is reduced and the speed can be increased. Well steps can be omitted. Latch-up can be prevented. Advantages such as the possibility of a fully depleted field-effect transistor by thinning can be obtained.

[0003] In order to realize many of the above advantages in device characteristics, researches have been made on a method of forming an SOI structure for several decades. This content can be found, for example, in Special Issue: "Single-crystal silicon on n
on-single-crystal insulators "; edited by GWCulle
n, Journal of Crystal Growth, volume 63, no3, pp 4
29-590 (1983).

Also, SOS (silicon-on-sapphire), which is formed by heteroepitaxy of Si on a single-crystal sapphire substrate by CVD (chemical vapor deposition), has been known for a long time. Although the technology achieved some success, a large number of crystal defects due to the lattice mismatch between the Si layer and the underlying sapphire substrate, contamination of aluminum from the sapphire substrate into the Si layer, and above all, the high cost of the substrate The delay in increasing the area has hindered the spread of its applications. 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 two. (1) After oxidizing the surface of the Si single crystal substrate, open a window to open the Si
The substrate is partially exposed, and the portion is epitaxially grown in the lateral direction using the seed as a seed to form a Si single crystal layer on SiO ₂ (in this case, a Si layer is deposited on SiO ₂ ). (2) using the Si single crystal substrate itself as an active layer,
SiO ₂ is formed thereunder (this method does not involve the deposition of a Si layer).

Various semiconductor devices and integrated circuits comprising them have been fabricated on a silicon layer on an insulator formed by these methods.

[0006]

As means for achieving the above (1), a single crystal layer Si is directly formed by a CVD method.
A method in which amorphous silicon is deposited and a solid-phase lateral epitaxial growth is performed by heat treatment, an electron beam is applied to an amorphous or polycrystalline Si layer.
A method of converging and irradiating an energy beam such as a laser beam to grow a single crystal layer on SiO ₂ by melting and recrystallization, and a method of scanning a melting region in a band shape by a rod heater (Zone melting recrystallization) are known. ing. Each of these methods has advantages and disadvantages,
There remain many problems in controllability, productivity, uniformity, and quality, and none has been industrially used yet. For example, the CVD method requires sacrificial oxidation to make a thin film flat, and the solid phase growth method has poor crystallinity. Further, the beam annealing method has a problem in controllability such as processing time by convergent beam scanning, beam overlap, focus adjustment, and the like. Of these, the Zone Melting Recrystallization method is the most mature, and although relatively large-scale integrated circuits have been prototyped, crystal defects such as sub-grain boundaries still remain.
There are many remaining, and there is no way to make a minority carrier device.

In the method (2) in which the Si substrate is not used as a seed for epitaxial growth, there are the following three methods.

[0008] 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, and then polished from the back surface of the Si substrate. Is to form a dielectrically separated Si single crystal region surrounded by V-grooves on a thick polycrystalline Si layer. In this method, the crystallinity is good, but polycrystalline Si is deposited several hundred microns thick.
Since a step of polishing the single crystal Si substrate from the back surface to leave only the separated Si active layer is required, there is a problem in terms of controllability and productivity.

[0009] Simox (SIMOX: Seperati
This is a method called “on by ion implanted oxygen” in which a SiO ₂ layer is formed by ion implantation of oxygen into a Si single crystal substrate, and is the most mature method at present because of its good compatibility with the Si process. However, in order to form a SiO ₂ layer, oxygen ions must be supplied at 10 ¹⁸ ions / cm ^2.
It is necessary to perform the above implantation, the implantation time is long, the productivity is not high, and the wafer cost is high. Furthermore, many crystal defects remain, and from an industrial point of view, the quality has not reached a level sufficient to produce a minority carrier device.

[0010] This is a method of forming an SOI structure by dielectric isolation by oxidation of porous Si. This method uses P
Ion implantation of N-type Si layer on the surface of single-crystal Si single crystal substrate (Imai et al., J. Crystal Growth, vol 63, 547 (1983)),
Alternatively, an island is formed by epitaxial growth and patterning, and only the P-type Si substrate is made porous by anodizing in an HF solution so as to surround the Si island from the surface. This is a method for dielectric isolation. 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. The features have not been fully demonstrated.

[0011]

According to the insulated gate field effect transistor of the present invention, at least the single crystal layer forming the channel region of the insulated gate field effect transistor is formed of a porous single crystal semiconductor layer and a nonporous single crystal semiconductor layer. Crystalline semiconductor layer and
And a semiconductor substrate with an insulating layer interposed therebetween,
A multi-layer structure in which the non-porous single-crystal semiconductor layer is located inside
Laminated so as to obtain, the porous structure from the multilayer structure
The semiconductor substrate obtained by removing the crystalline single crystal semiconductor layer
The non-porous single crystal provided thereon via the insulating layer
Characterized in that it is a layer .

Further, a semiconductor device according to the present invention is characterized in that the insulated gate field effect transistor is used.

Here, the semiconductor substrate includes an electronic circuit element such as a transistor, a metal wiring and the like.

[0014]

[Operation] Although the density of porous silicon is less than half that of single crystal Si, single crystallinity is maintained, and it is also possible to epitaxially grow a single crystal Si layer on top of a porous layer. It is possible. In addition, since the porous layer has a large amount of voids formed therein, the density is reduced to less than half. As a result, the surface area is dramatically increased as compared with the volume, so that the chemical etching rate is significantly increased as compared with the ordinary etching rate of the single crystal layer.

According to the present invention, utilizing such properties of porous silicon, a single-crystal semiconductor layer is formed on a silicon substrate having an oxide film on the surface, and an insulating gate type electric field is formed using the single-crystal semiconductor layer. This is for producing an effect transistor. That is, the present invention forms a non-porous single crystal layer having excellent crystallinity on a porous silicon substrate, and forms a surface of the non-porous single crystal layer or an oxidized surface of the non-porous single crystal layer. A step including, at least wet chemical etching, the porous silicon substrate obtained by bonding the silicon film having an oxide film on its surface to the oxide film and then increasing the etching rate as compared with a normal single crystal layer. To form a single-crystal semiconductor layer, and using this single-crystal semiconductor layer, an insulated gate field-effect transistor and a semiconductor device using the same are manufactured.

According to the present invention, there is provided a silicon substrate formed on a silicon substrate having an oxide film on its surface, which is excellent in economy, has uniform flatness over a large area, has extremely excellent crystallinity, and has extremely few defects. Since the element is created on the crystal layer, an insulated gate field effect transistor with reduced source and drain stray capacitance can be manufactured, high-speed operation is possible, and there is no latch-up phenomenon, etc. Semiconductor device can be provided.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic sectional view of one embodiment of a semiconductor device according to the present invention. In FIG. 1, a substrate 1 is a silicon substrate (to be a silicon substrate) having SiO ₂ (18 in FIG. 1) formed on its surface by selectively removing porous Si as described later.

An N-channel field-effect transistor 2 and a P-channel field-effect transistor 3 are formed on the substrate 1. By connecting both elements to each other, a complementary field-effect semiconductor device is manufactured.

Hereinafter, the steps of manufacturing the transistors 2 and 3 will be described with reference to FIGS. 2 and 3 from the step of manufacturing a single crystal semiconductor layer on an insulating substrate.

2 (a) to 2 (c) and 3 (a) to 3 (a).
(D) is a process drawing for explaining the method of manufacturing a semiconductor substrate according to the present invention, which is shown as a schematic cross-sectional view in each process. Note that, in FIG.
Substrate 21, thin film single crystal layer 22 is a porous single crystal semiconductor layer
(FIG. 2) having a member and a non-porous single crystal semiconductor layer
(A)), the substrate 23 is a semiconductor substrate, an oxide layer 24, an insulating layer
26 is an insulating layer, a porous Si single crystal substrate 21, a thin film single crystal
The layer 22, the oxide layer 24, the insulating layer 26, and the base 23 have a multilayer structure.
Body (FIG. 2B).

According to observation with a transmission electron microscope, pores having an average diameter of about 600 angstroms are formed in the porous Si layer, and the density thereof is less than half that of single crystal Si. Regardless, single crystallinity is maintained, and it is also possible to epitaxially grow a single crystal Si layer on the porous layer. However, 1000 ° C
Above, rearrangement of the internal holes occurs, and the characteristics of the accelerated etching are impaired. Therefore, the epitaxial growth of the Si layer includes molecular beam epitaxial growth, plasma CV
Low temperature growth such as D method, thermal CVD method, photo CVD method, bias sputtering method, liquid phase growth method, etc. is preferable.

First, a method for epitaxially growing a single crystal layer after making all the Si-P type substrate porous will be described. As shown in FIG. 2A, first, a Si single crystal substrate is prepared and made porous to form a porous Si single crystal substrate 21. Epitaxial growth is performed on the porous substrate surface by various growth methods to obtain a thin film single crystal layer 2.
Form 2 The Si substrate is made porous by an anodizing method using an HF solution. The porous Si layer, as compared with the density of 2.33 g / cm ³ of single crystal Si, by changing the density of HF solution concentration to 50 to 20%, a density 1.1~0.6g / cm It can be changed in the range of ³ . This porous layer is made of P-type S for the following reason.
It is easily formed on an i-substrate. According to observation with a transmission electron microscope, pores having an average diameter of about 600 angstroms are formed in the porous Si layer.

Porous Si is available from Uhlir et al.
Was discovered during the research process of electropolishing of semiconductors (A.
Uhlir, Bell Syst. Tech. J., vol 35, p.333 (1956)). In addition, 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 .
Unagami: J. Electrochem. Soc., Vol. 127, p. 476 (198
0)).

[0025] 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 - where _{SiF 4 + 2HF → H 2 SiF} 6, e + and, e ^- respectively represent a positive hole and an electron. Further, n and λ are the number of holes required for dissolving one atom of silicon, respectively, and it is assumed that porous silicon is formed when the condition of n> 2 or λ> 4 is satisfied.

From the above, P-type silicon having holes is made porous, while N-type silicon is not made porous. The selectivity in this porosity has been demonstrated by Nagano et al. And Imai (Nagano, Nakajima, Anno, Onaka, Kajiwara; IEICE Technical Report, vol 79, SSD 79-
9549 (1979), (K. Imai; Solid-State Electronics vol2
4,159 (1981)).

However, there is a report that high-concentration N-type Si can be made porous (RP Holmstrom and JYChi.
Appl. Phys. Lett. Vol. 42, 386 (1983)), it is important to select a substrate that can realize porosity regardless of whether it is a P-type or an N-type.

Further, the density of the porous layer is reduced to less than half since a large amount of voids are formed therein. As a result, the surface area increases dramatically compared to the volume,
The chemical etching rate is significantly increased compared to the etching rate of a normal single crystal layer.

As shown in FIG. 2B, the insulating layer 2 is formed on the surface.
6 is prepared, the surface of the single crystal Si layer on the porous Si substrate is oxidized, and then the insulating substrate 23 is attached to the oxide layer 24. The oxide layer plays an important role in making a device. That is, the interface level generated by the underlying interface of the Si active layer can be lower at the oxide film interface according to the present invention than at the interface directly bonded, and the characteristics of the electronic device are significantly improved. After bonding, the entire porous Si substrate 21 is removed by means of etching or the like, and a thinned single-crystal silicon layer 22 is left on the insulating substrate 23 to be formed.

FIG. 2C shows a semiconductor substrate obtained by the present invention. That is, the single-crystal Si layer 22 having crystallinity equivalent to that of a silicon wafer is flattened on the insulating substrate 23,
Moreover, the film is uniformly thinned and formed over a large area over the entire wafer. The semiconductor substrate obtained in this way can be suitably used from the viewpoint of producing an insulated electronic element.

A selective etching method for electrolessly wet etching only porous Si will be described below.

As an etching solution having no etching action on crystalline Si and capable of selectively etching only porous Si, hydrofluoric acid, buffered hydrofluoric acid, hydrofluoric acid added with aqueous hydrogen peroxide or buffered hydrofluoric acid can be used. A mixed solution of an acid, a mixed solution of hydrofluoric acid or buffered hydrofluoric acid to which an alcohol is added, and a mixed solution of hydrofluoric acid or buffered hydrofluoric acid to which an aqueous solution of hydrogen peroxide and an alcohol are added are suitably used. 4 to 11 show porous S
FIG. 7 is a characteristic diagram showing the etching time dependence of the thickness of the etched porous Si and single-crystal Si when i and single-crystal Si are infiltrated into the above various etching solutions. 4 are 49% hydrofluoric acid, FIG. 5 is a mixture of 49% hydrofluoric acid and hydrogen peroxide solution (1: 5), and FIG. 6 is a mixture of 49% hydrofluoric acid and alcohol ( 10: 1), FIG. 7 is 49%
A mixed solution of hydrofluoric acid, alcohol and aqueous hydrogen peroxide (10:
6:50) and FIG. 8 is buffered hydrofluoric acid, FIG.
Is a mixed solution of buffered hydrofluoric acid and aqueous hydrogen peroxide (1:
5), FIG. 10 shows a mixed solution of buffered hydrofluoric acid and alcohol (10: 1), and FIG. 11 shows a mixed solution of buffered hydrofluoric acid, alcohol and hydrogen peroxide solution (10: 6: 50). In addition, what added alcohol was infiltrated without stirring, and what added no alcohol was infiltrated with stirring.

The porous Si is prepared by anodizing single crystal Si and the conditions are as follows. The starting material of porous Si formed by anodization is not limited to single-crystal Si, but may be Si having another crystal structure.

Applied voltage: 2.6 (V) Current density: 30 (mA · cm ⁻² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 2.4 ( Time) Porous Si thickness: 300 (μm) Porosity: 56 (%) The porous Si prepared under the above conditions was infiltrated with the above various etching solutions at room temperature.

When the thickness of the porous Si was reduced by infiltrating it into 49% hydrofluoric acid (open circles in FIG. 4) with stirring, the porous Si was rapidly etched.
90 μm in about 40 minutes, and 20 minutes after 80 minutes
Even 5 μm was etched uniformly with a high degree of surface properties.

When a mixture of 49% hydrofluoric acid and aqueous hydrogen peroxide (1: 5) (open circles in FIG. 5) was infiltrated with stirring, the decrease in the thickness of the porous Si was measured. The porous Si is rapidly etched to 112 μm in about 40 minutes and 256 μm after 80 minutes.
Etching was uniform with high surface properties.

A mixture of 49% hydrofluoric acid and alcohol (1
0: 1) (open circles in FIG. 6) without infiltration, when the decrease in the thickness of the porous Si was measured, the porous Si was rapidly etched to 85 μm in about 40 minutes. 195 μm after 80 minutes
Also had a high degree of surface properties and was uniformly etched.

The thickness of the porous Si which was infiltrated without stirring into a mixed solution (10: 6: 50) of 49% hydrofluoric acid, alcohol and aqueous hydrogen peroxide (open circles in FIG. 7). As a result, the porous Si was rapidly etched, having a high surface property of 107 μm in about 40 minutes and 244 μm after 80 minutes, and was uniformly etched.

When a decrease in the thickness of the porous Si was measured with respect to a sample in which buffered hydrofluoric acid (open circles in FIG. 8) was stirred and infiltrated, the porous Si was rapidly etched.
70 μm in about 0 minutes, and 11 after 120 minutes.
Even 8 μm was etched uniformly with a high degree of surface properties.

When a mixture of buffered hydrofluoric acid and aqueous hydrogen peroxide (1: 5) (open circles in FIG. 9) was infiltrated and stirred, a decrease in the thickness of the porous Si was measured.
Porous Si is rapidly etched to 88
μm, and even 147 μm after 120 minutes, had a high degree of surface properties and were uniformly etched.

When a mixture of buffered hydrofluoric acid and alcohol (10: 1) (open circles in FIG. 10) was infiltrated without stirring, the decrease in the thickness of the porous Si was measured. The porous Si is rapidly etched and
67 μm in about 0 minutes, and 11 after 120 minutes.
Even 2 μm was uniformly etched with a high degree of surface properties.

The thickness of the porous Si that was infiltrated without stirring into a mixed solution (10: 6: 50) of buffered hydrofluoric acid, alcohol and aqueous hydrogen peroxide (open circles in FIG. 11) As a result, the porous Si was rapidly etched to 83 μm in about 40 minutes,
After 0 minutes, 140 μm was uniformly etched with a high degree of surface properties.

Although the solution concentration of the hydrogen peroxide solution is 30% here, it is set at a concentration that does not impair the effect of adding the following hydrogen peroxide solution and that is practically acceptable in the manufacturing process and the like. You. As buffered hydrofluoric acid, ammonium fluoride (NH ₄ F) 36.2%, hydrogen fluoride (HF)
A 4.46% aqueous solution is used.

The etching rate depends on the solution concentration and temperature of hydrofluoric acid, buffered hydrofluoric acid and aqueous hydrogen peroxide.
By adding the hydrogen peroxide solution, the oxidation of silicon can be accelerated, and the reaction rate can be increased as compared with the case without addition. By further changing the ratio of the hydrogen peroxide solution, the reaction rate can be increased. Can be controlled. In addition, by adding alcohol, bubbles of the reaction gas generated by the etching can be instantaneously removed from the etching surface without stirring, and the porous Si can be uniformly and efficiently etched.

The conditions of the solution concentration and the temperature are set within a range in which the effects of hydrofluoric acid, buffered hydrofluoric acid and the above-mentioned hydrogen peroxide solution or the above-mentioned alcohol are exerted, and the etching rate is practically acceptable in the manufacturing process and the like.

In the present application, the case of the above-mentioned solution concentration and room temperature is taken as an example, but the present invention is not limited to such conditions.

The HF concentration in the buffered hydrofluoric acid is preferably set in the range of 1 to 95%, more preferably 1 to 85%, and still more preferably 1 to 70% with respect to the etching solution. The NH ₄ F concentration in the acid is set in the range of preferably 1 to 95%, more preferably 5 to 90%, and still more preferably 5 to 80% with respect to the etching solution.

The HF concentration is set in the range of preferably 1 to 95%, more preferably 5 to 90%, and still more preferably 5 to 80% with respect to the etching solution.

The H ₂ O ₂ concentration depends on the etching solution.
It is preferably set in the range of 1 to 95%, more preferably 5 to 90%, and still more preferably 10 to 80%, and within a range in which the above-mentioned effect of the hydrogen peroxide solution is exhibited.

The alcohol concentration is set to preferably 80% or less, more preferably 60% or less, and still more preferably 40% or less with respect to the etching solution, and is set within a range in which the effect of the alcohol is exerted.

The temperature is set in the range of preferably 0 to 100 ° C., more preferably 5 to 80 ° C., and still more preferably 5 to 60 ° C.

As the alcohol used in the present invention, besides ethyl alcohol, an alcohol such as isopropyl alcohol which can be practically used in the production process and the like and which can achieve the above-mentioned effect of adding alcohol can be used.

Further, non-porous Si having a thickness of 500 μm was infiltrated into the above-mentioned various etching solutions at room temperature. Later
The decrease in thickness of the non-porous Si was measured. Non-porous Si
Was etched only 100 angstroms or less even after elapse of 120 minutes.

Porous Si and Non-porous Si after Etching
Was washed with water and the surface thereof was trace-analyzed with secondary ions. As a result, no impurities were detected.

Hereinafter, another method of manufacturing a semiconductor substrate according to the present invention will be described in detail with reference to the drawings.

FIGS. 3A to 3D are process diagrams for explaining another method of manufacturing a semiconductor substrate according to the present invention, and are shown as schematic cross-sectional views in each process. In addition,
3, a porous Si substrate 33, a single-crystal Si layer 32
Has a porous single-crystal semiconductor layer and a non-porous single-crystal semiconductor layer.
(FIG. 3 (b)), having an insulating layer 36
The substrate 34 is a semiconductor substrate having an insulating layer, and the insulating layer 36 is
Edge layer, porous Si substrate 33, single-crystal Si layer 32, insulating layer
36, semiconductor substrate (insulating substrate 34 excluding insulating layer 36)
Is a multilayer structure (FIG. 3C).

First, as shown in FIG. 3A, a low impurity concentration layer 32 is formed on a high concentration silicon single crystal substrate 31 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 31 to form the N-type single-crystal layer 32.

Next, as shown in FIG.
The single crystal substrate 31 is transformed from the rear surface into a porous Si substrate 33 by an anodizing method using an HF solution. The porous Si layer, the monocrystalline Si as compared with the density of 2.33 g / cm ^3, the density of 1.1~0.6g / cm ³ by changing the density of HF solution concentration to 50 to 20% Range. This porous layer is formed on a P-type substrate as described above.

As shown in FIG. 3C, the insulating layer 3 is formed on the surface.
6 is prepared, and the insulating substrate is attached to the surface of the single crystal Si layer on the porous Si substrate. As shown in FIG. 3C, the porous Si substrate 33 is removed by etching to leave a thin single-crystal silicon layer on the insulating substrate.

FIG. 3D shows a semiconductor substrate obtained by the present invention. That is, the single-crystal Si layer 32 having a crystallinity equivalent to that of a silicon wafer is flattened on the insulating substrate 34,
Moreover, the film is uniformly thinned and 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 above is a method in which an N-type layer is formed before the formation of the porous body, and thereafter, only the P-type substrate is selectively made porous by anodizing.

Next, the single-crystal thin layer on the surface of the insulating substrate thus manufactured is separated by a partial oxidation method or an island-like etching as shown in FIG. Next, a P-type impurity ion on a single-crystal silicon island (4 in FIG. 1) for forming an N-channel transistor (2 in FIG. 1), and a single-crystal silicon for forming a P-channel transistor (3 in FIG. 1). N-type impurity ions are independently implanted into the islands (5 in FIG. 1).

Next, a gate insulating film (6, 7 in FIG. 1) is formed on each single-crystal silicon layer (4, 5 in FIG. 1), and a polycrystalline silicon gate electrode (8, 7 in FIG. 1) is formed.
9) is formed by patterning.

Using the polycrystalline silicon gate electrode as a mask, impurity ions are implanted in a self-aligned manner to form source and drain regions. For the N-channel transistor (2 in FIG. 1), N-type impurity ions are implanted to form a source (10 in FIG. 1) and a drain region (11 in FIG. 1).
For the P-channel transistor (3 in FIG. 1), P-type impurity ions are implanted into the source (1 in FIG. 1).
2) and a drain region (13 in FIG. 1). Source and drain electrodes (14, 15, 16, and 17 in FIG. 1) are formed by depositing and patterning a metal thin film to complete the device. By connecting the elements to each other by a thin film electrode, a complementary field effect transistor is manufactured.

[0066]

The present invention will be described below with reference to specific examples. In the embodiments described below, a case where a mixed solution (10: 6: 50) of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10: 6: 50) is used as an etching solution will be described as an example. It is needless to say that the etching solution can also be used in the same manner. (Example 1) P-type (10
0) A single crystal Si substrate was anodized in an HF solution.

The anodizing conditions were as follows.

Applied voltage: 2.6 (V) Current density: 30 (mA · cm ⁻² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 1.6 ( Time) Thickness of porous Si: 200 (μm) Porosity: 56 (%) MBE (Molecular Beam Epitaxy) on the P-type (100) porous Si substrate
An axy) method was used to grow a Si epitaxial layer at a low temperature of 0.5 μm. The deposition conditions are as follows.

Temperature: 700 ° C. Pressure: 1 × 10 ⁻⁹ Torr Growth rate: 0.1 nm / sec Next, an oxide layer of 1000 Å is formed on the surface of this epitaxial layer,
The other Si substrate on which an oxide layer having a thickness of 2,000 Å is formed is superimposed, and is placed at 800 ° C., 0.
By heating for 5 hours, both Si substrates were firmly joined.

After that, the bonded substrate was mixed with a mixture of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution is extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed and a single-crystal Si substrate having a thickness of 0.5 μm is formed on SiO _2.
A layer could be formed.

As a result of the 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.

A field effect transistor was formed on the single crystal silicon thin film and connected to each other to manufacture a complementary element and an integrated circuit thereof. Note that the method of manufacturing each transistor is omitted because a known MOS integrated circuit manufacturing technique is used, and only a substantial method of forming a single crystal semiconductor layer has been described. The same applies to the following embodiments. (Example 2) P-type (10
0) A single crystal Si substrate was anodized in an HF solution.

The anodizing conditions were as follows.

Applied voltage: 2.6 (V) Current density: 30 (mA · cm ⁻² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 1.6 ( Time) Thickness of porous Si: 200 (μm) Porosity: 56 (%) On the P-type (100) porous Si substrate, a Si epitaxial layer was grown at a low temperature of 0.5 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, an oxide layer of 1000 Å is formed on the surface of the epitaxial layer, and the oxide surface is formed on the oxide surface. , 5 on the surface
The other Si substrate on which an oxide layer having a thickness of 2,000 Å is formed is superimposed, and is placed at 800 ° C., 0.
By heating for 5 hours, both Si substrates were firmly joined.

Thereafter, the bonded substrate was mixed with a mixed solution of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution is extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed and a single-crystal Si substrate having a thickness of 0.5 μm is formed on SiO _2.
A layer could be formed. A field effect transistor was fabricated on the single crystal silicon thin film and connected to each other to fabricate a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor. (Example 3) P-type (10
0) A single crystal Si substrate was anodized in an HF solution.

The anodizing conditions were as follows.

Applied voltage: 2.6 (V) Current density: 30 (mA · cm ⁻² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 1.6 ( Time) Porous Si thickness: 200 (μm) Porosity: 56 (%) On the P-type (100) porous Si substrate, a Si epitaxial layer was grown at a low temperature of 0.5 μm by a bias sputtering method. The deposition conditions are as follows.

[0080] RF frequency: 100 MHz _Z frequency power: 600W Temperature: 300 ° C. Ar gas pressure: 8 × 10 ^-3 Torr Growth time: 60 minutes Target direct current bias: -200 V substrate direct current bias: + 5V Next, the surface of the epitaxial layer An oxide layer of 1000 Å is formed on the oxidized surface and 5 Å on the surface.
The other Si substrate on which an oxide layer having a thickness of 2,000 Å is formed is superimposed, and is placed at 800 ° C., 0.
By heating for 5 hours, both Si substrates were firmly joined.

After that, the bonded substrate was mixed with a mixture of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution is extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed and a single-crystal Si substrate having a thickness of 0.5 μm is formed on SiO _2.
A layer could be formed.

A field effect transistor was formed on the single crystal silicon thin film and connected to each other to manufacture a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor. (Example 4) N-type (10
0) A single crystal Si substrate was anodized in an HF solution.

The anodizing conditions were as follows.

Applied voltage: 2.6 (V) Current density: 30 (mA · cm ⁻² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 1.6 ( Time) Thickness of porous Si: 200 (μm) Porosity: 56 (%) On the N-type (100) porous Si substrate, a Si epitaxial layer was grown at a low temperature of 5 μm by a liquid phase growth method. The growth conditions are as follows.

Solvent: Sn temperature: 900 ° C. Growth atmosphere: H ₂ growth time: 50 minutes Next, an oxide layer of 1000 Å was formed on the surface of the epitaxial layer, and 5 Å was formed on the oxidized surface.
The other Si substrate on which an oxide layer having a thickness of 2,000 Å is formed is superimposed, and is placed at 800 ° C., 0.
By heating for 5 hours, both Si substrates were firmly joined.

After that, the bonded substrates were mixed with a mixed solution of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution is extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 μm was removed, and a single-crystal Si layer having a thickness of 5 μm was formed on SiO ₂ .

A field effect transistor was formed on the single crystal silicon thin film and connected to each other, thereby manufacturing a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor. (Example 5) P-type (10
0) A single crystal Si substrate was anodized in an HF solution.

The anodizing conditions were as follows.

Applied voltage: 2.6 (V) Current density: 30 (mA · cm ⁻² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 1.6 ( Time) Thickness of porous Si: 200 (μm) Porosity: 56 (%) On the P-type (100) porous Si substrate, a Si epitaxial layer was grown at a low temperature of 1.0 μm by a 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 of 1000 Å is formed on the surface of this epitaxial layer, and its oxidation is performed. 5 on the surface, on the surface
The other Si substrate on which an oxide layer having a thickness of 2,000 Å is formed is superimposed, and is placed at 800 ° C., 0.
By heating for 5 hours, both Si substrates were firmly joined.

Then, the bonded substrates were mixed with a mixture of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution is extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed and a single-crystal Si substrate having a thickness of 1.0 μm is formed on SiO _2.
A layer could be formed. 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.

A field effect transistor was formed on the single-crystal silicon thin film and connected to each other to manufacture a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor. (Example 6) P-type (10
0) A Si epitaxial layer was grown on a Si substrate by 1 μm 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 was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / mi.
n. And a P-type (10
0) The entire Si substrate was made porous in 24 minutes. As described above, in this anodization, only the P-type (100) Si substrate was made porous and the Si epitaxial layer did not change.

Next, 10 .ANG.
A 2,000-Å-thick oxidized layer was formed, and another Si substrate having a 5,000-Å-thick oxidized layer formed on the oxidized surface was placed thereon.
By heating at 00 ° C. for 0.5 hour, both Si substrates were firmly joined.

Then, the bonded substrate was mixed with a mixture of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution is extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed,
A single-crystal Si layer having a thickness of 1.0 μm was formed on SiO ₂ .

As a result of observing the cross section with a transmission electron microscope,
No new crystal defects were introduced into the i-layer, and it was confirmed that good crystallinity was maintained.

A field effect transistor was formed on the single crystal silicon thin film and connected to each other to manufacture a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor. (Example 7) P-type (10
0) A 5 μm Si epitaxial layer was grown on a Si substrate by atmospheric pressure 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: 760 Torr Time: 1 min. The Si substrate was anodized in an HF solution.

The anodizing conditions were as follows.

Applied voltage: 2.6 (V) Current density: 30 (mA · cm ⁻² ) Anodizing solution: HF: H ₂ O: C ₂ H ₅ OH = 1: 1: 1 Time: 1.6 ( Time) Porous Si thickness: 200 (μm) Porosity: 56 (%) As described above, in this anodization, P-type (100) Si
Only the substrate was made porous, and there was no change in the Si epitaxial layer.

Next, 10 .ANG.
A 2,000-Å-thick oxidized layer was formed, and another Si substrate having a 5,000-Å-thick oxidized layer formed on the oxidized surface was placed thereon.
By heating at 00 ° C. for 0.5 hour, both Si substrates were firmly joined.

Then, the bonded substrate was mixed with a mixture of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution is extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed,
A single-crystal Si layer having a thickness of 5 μm was formed on SiO ₂ .

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

A field effect transistor was formed on the single-crystal silicon thin film and connected to each other to manufacture a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor. (Example 8) A P-type (10
0) By ion implantation of protons on the surface of the Si substrate, N
A 1-micron type Si layer was formed. H ⁺ injection volume is 5 × 1
0 ¹⁵ (ions / cm ² ). 50% of this substrate
In an HF solution of 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 having a thickness of 200 microns was made porous in 24 minutes. As described above, in this anodization,
Only the P-type (100) Si substrate was made porous, and the N-type Si layer did not change. Next, 1 N is applied to the surface of the N-type Si layer.
A 2,000 Å oxide layer is formed, and another Si substrate having a 5000 Å oxide layer formed on the oxidized surface is superimposed thereon, and heated at 800 ° C. for 0.5 hour in an oxygen atmosphere. Si
The substrate was firmly bonded.

After that, the bonded substrates were mixed with a mixed solution of 49% hydrofluoric acid, alcohol and 30% hydrogen peroxide solution (10:
6:50), selective etching is performed without stirring.
After 65 minutes, only the single crystal Si layer remained without being etched, and the porous Si substrate was selectively etched using the single crystal Si as an etch stop material, and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution was extremely low, even after 65 minutes.
Angstroms or less, the selectivity with respect to the etching rate of the porous layer reaches more than ten-fiveth power, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed and a single-crystal Si substrate having a thickness of 1.0 μm is formed on SiO _2.
A layer could be formed.

As a result of observation of a cross section by 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 9) A P-type (10
0) A single crystal Si substrate was anodized in a 50% HF solution. The current density at this time was 10 mA / cm ²
Met. A porous layer having a thickness of 20 microns was formed on the surface in 10 minutes. On the P-type (100) porous Si substrate, a Si epitaxial layer was grown at a low temperature of 0.5 μm by a low pressure CVD method. The deposition conditions are as follows.

Gas: SiH ₂ Cl ₂ (0.6 1 / min.), H ₂ (100 1 / min) Temperature: 850 ° C. Pressure: 50 Torr Growth rate: 0.1 μm / min Next, the surface of this epitaxial layer Was thermally oxidized by 50 nm. A silicon substrate having an oxide layer of 0.8 μm on the surface is superposed on the thermal oxide film, and 900 μm in an oxygen atmosphere.
By heating at 1.5 ° C. for 1.5 hours, the two substrates were firmly joined.

Thereafter, 490 from the back surface of the silicon substrate
It was removed by micron grinding to expose the porous layer.

Then, the bonded substrate was mixed with a mixed solution of 49% hydrofluoric acid, alcohol and hydrogen peroxide (10: 6: 5).
In step 0), selective etching is performed without stirring. After 15 minutes, only the single crystal Si layer remains without being etched,
Using single crystal Si as an etch stop material, porous S
The i-layer was selectively etched and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution was extremely low, and the etching rate was 40 minutes even after 15 minutes.
The selectivity with the etching rate of the porous layer reaches about 10 times or more, and the etching amount (several angstroms) in the non-porous layer is a thickness reduction that can be ignored in practical use. A single-crystal Si layer having a thickness of 0.5 μm was formed on a silicon substrate having an insulating layer on the surface.

A field effect transistor was formed on the single-crystal silicon thin film and connected to each other to manufacture a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor. (Example 10) A P-type (1
00) A 1 micron Si epitaxial layer was grown on the Si substrate by CVD. The deposition conditions are as follows.

Reaction gas flow rate: SiH ₂ Cl ₂ 1000 SCCM H ₂ 230 1 / 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 was 100 mA / cm ² . At this time, the rate of making porous is 8.4 μm / mi.
n. And a P-type (10
0) The entire Si substrate was made porous in 24 minutes. As described above, in this anodization, only the P-type (100) Si substrate was made porous, and the Si epitaxial layer did not change.

Next, the surface of this epitaxial layer is coated with 0.1.
A silicon substrate having an oxide layer of 8 microns on the surface was overlaid and heated in an oxygen atmosphere at 900 ° C. for 1.5 hours, whereby both substrates were firmly joined.

Thereafter, the bonded substrate was mixed with a mixture of 49% hydrofluoric acid, alcohol and aqueous hydrogen peroxide (10: 6: 5).
In step 0), selective etching is performed without stirring. After 65 minutes, only the single crystal Si layer remains without being etched,
Using single crystal Si as an etch stop material, porous S
The i-substrate was selectively etched and completely removed.

The etching rate of the non-porous Si single crystal with respect to the etching solution was extremely low, and the etching rate was 40 minutes even after 65 minutes.
The selectivity with the etching rate of the porous layer reaches about 10 times or more, and the etching amount (several tens of angstroms) in the non-porous layer is a practically negligible decrease in film thickness. That is, the porous Si substrate having a thickness of 200 microns is removed,
A single-crystal Si layer having a thickness of 1 μm was formed on the insulating substrate.

As a result of observing the cross section with a transmission electron microscope,
No new crystal defects were introduced into the i-layer, and it was confirmed that good crystallinity was maintained. A field effect transistor was fabricated on the single crystal silicon thin film and connected to each other to fabricate a complementary element and an integrated circuit thereof. A known MOS integrated circuit manufacturing technique is used for the method of manufacturing each transistor.

[0122]

As described in detail above, according to the insulated gate field effect transistor and the semiconductor device using the same of the present invention, a high quality single crystal layer formed on an insulating substrate has high performance. An insulated gate field effect transistor is manufactured. Therefore, the insulating substrate has a small stray capacitance and can operate at high speed, and has sufficient latch-up phenomena.
An integrated circuit that can exhibit various advantages as an OI element can be provided at a low price.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a complementary insulated gate field effect transistor according to the present invention.

FIG. 2 is a schematic cross-sectional view for explaining a substrate manufacturing step of the present invention.

FIG. 3 is a schematic sectional view for explaining a process of the present invention.

FIG. 4 shows etching characteristics of porous and non-porous Si.

FIG. 5 shows the etching characteristics of porous and non-porous Si.

FIG. 6 shows etching characteristics of porous and non-porous Si.

FIG. 7 shows etching characteristics of porous and non-porous Si.

FIG. 8 shows etching characteristics of porous and non-porous Si.

FIG. 9 shows etching characteristics of porous and non-porous Si.

FIG. 10 shows etching characteristics of porous and non-porous Si.

FIG. 11 shows etching characteristics of porous and non-porous Si.

[Explanation of symbols]

1 substrate, 2 N-channel field effect transistor, 3
P-channel field effect transistor, 4 island-shaped single crystal layer, 5 island-shaped single crystal layer, 6 gate oxide film, 7 gate oxide film, 8 gate electrode, 9 gate electrode, 1
0 source region, 11 drain region, 12 source region, 13 drain region, 14 source electrode, 1
5 drain electrode, 16 source electrode, 17 drain electrode, 18 surface insulating layer, 21 porous Si substrate,
22 non-porous Si single crystal layer, 23 substrate, 24
Silicon oxide layer, 26 silicon oxide layer, 31 P-type Si single crystal substrate, 32 N-type Si single crystal layer, 33 porous Si substrate, 34 substrate, 36 silicon oxide layer.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI H01L 27/12 (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 29/786 H01L 21/02 H01L 21/336 H01L 21/8238 H01L 27/092 H01L 27/12

Claims (5)

(57) [Claims] 1. An insulated gate field effect transistor, comprising:
At least the single crystal layer forming the channel region has a porous single crystal semiconductor layer and a non-porous single crystal semiconductor layer.
And the semiconductor substrate via an insulating layer.
A multi-layered structure with a porous single-crystal semiconductor layer located inside was obtained.
And bonding the porous unit from the multilayer structure.
On the semiconductor substrate obtained by removing the crystalline semiconductor layer
An insulated gate field effect transistor which is the non-porous single crystal layer provided via the insulating layer . 2. The insulated gate field effect transistor according to claim 1, wherein the channel region of the insulated gate field effect transistor is an N-type channel. 3. The insulated gate field effect transistor according to claim 1, wherein the channel region of the insulated gate field effect transistor is a P-type channel. 4. The insulated gate field effect transistor according to claim 2,
4. A transistor and an insulated gate field effect transistor according to claim 3.
Insulated gate field effect transistor of complementary and a Njisuta. 5. A semiconductor device comprising the insulated gate field effect transistor according to claim 2, 3 or 4.