JPH11307471A - Manufacture for soi substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have great gettering capability and eliminate contamination on a semiconductor layer with heavy metal impurities an SOI substrate in which the semiconductor layers made by use of hydrogen ion injection art are superimposed on a semiconductor substrate via an oxide film. SOLUTION: An oxide film 12 is formed on a surface of a p-type first silicon substrate 11. Hydrogen ions are injected from a surface of a first substrate to form a hydrogen ion injection region 11a inside the substrate. A p<+> -type or p<++> polysilicon layer 14 is formed on one face of a p-type second silicon substrate 13 to be a support substrate. A p-type polysilicon layer 16 is formed on the polysilicon layer 14 to be ground. The second substrate is superimposed on the first substrate so that this polysilicon layer 16 is closely adhered to the oxide film, to be closely adhered to each other. The first substrate is closely adhered to the second substrate to heat them, while the first substrate is separated from the second substrate in a hydrogen ion injection region 11a to form a silicon layer 11b on a surface of the second substrate. The second substrate is further heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SO film having a semiconductor layer provided on an insulating film manufactured by using a hydrogen ion implantation technique.
The present invention relates to a method for manufacturing an I (Silicon On Insulator) substrate.

[0002]

2. Description of the Related Art An SOI substrate of this kind has attracted attention as a future ultra-high integrated circuit (ULSI) substrate. This S
The method of manufacturing an OI substrate includes a method of bonding silicon substrates to each other via an insulating film, a method of depositing a silicon thin film on an insulating substrate or a substrate having an insulating thin film on the surface, and a method of forming a high-concentration silicon inside a silicon substrate. After implanting oxygen ions, annealing is performed at a high temperature to form a buried silicon oxide layer at a predetermined depth from the surface of the silicon substrate, and there is a SIMOX method using the Si layer on the surface as an active region. . Also, recently, after implanting hydrogen ions or the like into a semiconductor substrate, the semiconductor substrate is superimposed on a support substrate with the ion-implanted surface as an overlapping surface, and this laminate is
A method for producing a thin semiconductor material film having a semiconductor thin film on the surface of a supporting substrate has been proposed in which the temperature of the semiconductor substrate is raised to a temperature exceeding ℃ to separate the semiconductor substrate from the supporting substrate in a region where the hydrogen ions or the like are implanted. (JP-A-5-21112
8). According to this method, a semiconductor substrate having a thin semiconductor layer having a uniform thickness can be obtained if ions can be uniformly implanted into the inside of the semiconductor substrate from the surface. If an oxide film is provided on the surface of the support substrate in advance, the method has a support substrate, an oxide film formed on the substrate and acting as a buried oxide film, and a semiconductor layer formed on the oxide film. SO
An I substrate can be manufactured.

[0003]

However, if the semiconductor layer formed on the oxide film is contaminated by heavy metal impurities during the device process, the buried oxide film may be replaced with a gettering layer having gettering ability. After the heavy metal impurities are trapped, the oxide layer crystallized with the progress of the heat treatment releases the trapped heavy metal impurities into the semiconductor layer and tends to redistribute, thereby causing contamination of the semiconductor layer. There is a problem that the quality is deteriorated due to this. An object of the present invention is to provide a SOI in which a semiconductor layer formed by using a hydrogen ion implantation technique is superposed on a semiconductor substrate via an oxide film.
An object of the present invention is to provide a method for manufacturing an SOI substrate which has a large gettering ability and does not contaminate a semiconductor layer with heavy metal impurities.

[0004]

The invention according to claim 1 is
As shown in FIG. 1, a step of forming an oxide film 12 on the surface of a p-type first silicon substrate 11,
Implanting hydrogen ions from the surface of the first silicon substrate 11
A step of forming a hydrogen ion implanted region 11a therein and a step of forming p ^{+ on} one surface of a p-type second silicon substrate 13 serving as a support substrate;
Forming a p-type or p ⁺⁺ -type polysilicon layer 14;
Forming a type polysilicon layer 16, the p ^{- -} p on p ⁺ -type or p ⁺⁺ type polysilicon layer 14 of the second silicon substrate 13 and the step of mirror polishing the polysilicon layer 16 of the mold A step of superimposing the second silicon substrate 13 on the first silicon substrate 11 so that the p ⁻ type polysilicon layer 16 is in close contact with the oxide film 12, and attaching the first silicon substrate 11 to the second silicon substrate 13. The first silicon substrate 11 is separated from the second silicon substrate 13 in the hydrogen ion implanted region 11a by performing a heat treatment at a predetermined temperature with
An SOI substrate manufacturing method includes a step of forming a silicon layer 11b on the surface of a silicon substrate 13 and a step of further heat-treating the second silicon substrate 13 having the silicon layer 11b on the surface. As shown in FIG. 1, a p ⁻ type polysilicon layer 16 and a p ⁺ type or p ⁺⁺ type polysilicon layer 14 are formed below and in close contact with the oxide film 12. Even if the layer 11b is contaminated by heavy metal impurities during the device process, the p ^- type polysilicon layer 16
And the p ⁺ type or p ⁺⁺ type polysilicon layer 14 functions as a gettering layer. This is because the silicon grain boundaries in the polysilicon layer getter heavy metal impurities. Further, defects are likely to occur in the p ⁺ type or p ⁺⁺ type polysilicon layer. This defect increases gettering ability. Further, since boron forms a stable iron-boron pair with heavy metal impurities such as iron, the gettering ability with respect to heavy metal impurities is also high in the p ⁺ type or p ⁺⁺ type polysilicon layer having a high boron concentration. high.
That is, the heavy metal impurities in the silicon layer 11b
Through the p ^- type polysilicon layer 16 and the p ⁺ type or p
^The silicon layer 11b is trapped by the ⁺⁺ type polysilicon layer 14 and is not contaminated with heavy metal impurities even if the heat treatment proceeds.
Also, an oxide film 12 and a p ⁺ type or p ⁺⁺ type polysilicon layer 1 are formed.
Since the type polysilicon layer 16 is formed, the p ^{- -} is between 4 p by changing combined thickness of the type polysilicon layer 16 in device design, silicon layer 1
The effect on the expansion of the depletion layer during operation of the device formed in 1b can be suppressed.

According to a second aspect of the present invention, as shown in FIG. 2, a step of forming an oxide film 12 on the surface of a p-type first silicon substrate 11 and implanting hydrogen ions from the surface of the first silicon substrate 11 Forming a hydrogen ion implanted region 11a inside the first silicon substrate 11 by using
Forming a phosphorus-implanted layer 13a in the second silicon substrate 13 by ion-implanting phosphorus from the surface of the second silicon substrate 13 of the mold; A step of superimposing the second silicon substrate 13 on the first silicon substrate 11 and bringing the second silicon substrate 13 into close contact therewith, and performing a heat treatment at a predetermined temperature while keeping the first silicon substrate 11 in close contact with the second silicon substrate 13 so that the first silicon substrate 11 is exposed to hydrogen ions. Forming a silicon layer 11b on the surface of the second silicon substrate 13 separated from the second silicon substrate 13 in the implantation region 11a, and forming a second layer having the silicon layer 11b on the surface.
Further heat-treating the silicon substrate 13.
This is a method for manufacturing a substrate. As shown in FIG.
Inside the second silicon substrate 13 below the
Since the layer 3a is formed, even if the silicon layer 11b is contaminated with heavy metal impurities during the device process, the phosphorus injection layer 13a functions as a gettering layer. This is due to the defect generated by the phosphorus implantation and the increase in the solid solubility limit of the metal element due to the introduction of phosphorus. That is, the heavy metal impurities in the silicon layer 11b pass through the oxide film 12 and are captured by the phosphorus implantation layer 13a, and the silicon layer 11b is not contaminated by the heavy metal impurities even if the heat treatment proceeds.

According to a third aspect of the present invention, as shown in FIG. 3, a step of forming an oxide film 12 on the surface of a p-type first silicon substrate 11 and implanting hydrogen ions from the surface of the first silicon substrate 11 Forming a hydrogen ion implanted region 11a inside the first silicon substrate 11 by using
Forming a phosphorus-implanted layer 13a within the second silicon substrate 13 by phosphorus ion implantation from the surface of the second silicon substrate 13 of the mold, p on the surface of the second silicon substrate 13 formed with phosphorus implantation layer 13a ^- Forming the p ^- type polysilicon layer 16, mirror-polishing the p ^- type polysilicon layer 16, and forming the first polysilicon layer 16 so that the mirror-polished p ^- type polysilicon layer 16 adheres to the oxide film 12. Silicon substrate 1
1. a step of superimposing the second silicon substrate 13 on the first silicon substrate 13 and a step of heat-treating the first silicon substrate 11 at a predetermined temperature while keeping the first silicon substrate 11 in close contact with the second silicon substrate 13 so as to bring the first silicon substrate 11 into the hydrogen ion implanted region 11a. Forming a silicon layer 11b on the surface of the second silicon substrate 13 by separating the silicon layer 11b from the second silicon substrate 13;
And a step of further heat-treating the second silicon substrate 13 having the following. As shown in FIG. 3, since the phosphorus implantation layer 13a is formed inside the second silicon substrate 13 below the oxide film 12, even if the silicon layer 11b is contaminated by heavy metal impurities during the device process, The P ⁻ type polysilicon layer 16 and the phosphorus implantation layer 13a function as gettering layers. That is, the heavy metal impurities in the silicon layer 11b pass through the oxide film 12 and are captured by the phosphorus implantation layer 13a, and the silicon layer 11b is not contaminated by the heavy metal impurities even if the heat treatment proceeds. Oxide film 1
Since the type polysilicon layer 16 is formed, the p ^{- -} p is between 2 and phosphorus injection layer 13a by changing the combined thickness of the type polysilicon layer 16 in device design, silicon layer The effect on the expansion of the depletion layer during the operation of the element formed in 11b can be suppressed.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. As shown in FIG. 1, in order to manufacture the SOI substrate according to the first embodiment of the present invention, first, a p-type first
A single crystal silicon substrate 11 is prepared. The first single crystal substrate 11 is manufactured by using boron (B) as a dopant. An oxide film 12 as an insulating layer is formed on the surface of the first single crystal substrate 11 by thermal oxidation.
(A)). This oxide film 12 is formed to have a thickness of 0.1 to 2 μm, preferably 0.1 to 0.5 μm.
Next, hydrogen ions are implanted from the surface of the p-type single crystal substrate 11 having the oxide film 12 with a dose of 1 to 10 × 10 ¹⁶ / cm ² and an acceleration energy of 50 to 200 keV. As a result, an ion implantation region 11a is formed inside the single crystal substrate 11 (FIG. 1B). Next, a p-type second single-crystal silicon substrate 13 having the same surface area as the single-crystal substrate 11 and serving as a support substrate is prepared, and the surface of the second single-crystal substrate 13 is p ⁺ -type or p ^{+ A +} type polysilicon layer 14 is formed (FIG. 1C). The p ⁺ -type or p ⁺⁺ -type polysilicon layer 14 is a p-type first single crystal substrate 1.
It is formed with a higher concentration of boron as a dopant than 1. This polysilicon layer 14 is formed to have a thickness of 0.5 to 3 μm, preferably 0.5 to 2 μm. Then, the p ⁺ type or p ⁺⁺ type polysilicon layer 14 is formed.
A p ^- type polysilicon layer 16 is formed thereon (FIG. 1).
(D)). The p ^- type polysilicon layer 16 has a thickness of 0.5 to
It is formed to have a thickness of 3 μm, preferably 0.5 to 2 μm. The p ⁻ type polysilicon layer 16 is formed with a lower boron concentration than the p ⁺ type or p ⁺⁺ type polysilicon layer 14. Preferably, it is equivalent to the first single crystal substrate 11. Next, the p ⁻ type polysilicon layer 16 is mirror-polished and flattened. Next, after cleaning the first single crystal substrate 11 and the second single crystal substrate 13 respectively, the first single crystal substrate 1 is so bonded that the p ⁻ type polysilicon layer 16 is in close contact with the oxide film 12.
The second single crystal substrate 13 is superimposed on and adhered to the substrate 1 (FIG. 1E). Then, the first single crystal substrate 11 is kept in close contact with the second single crystal substrate 13 in a nitrogen atmosphere at 500 to 800
The temperature is raised to the range of ° C., and the film is held for 5 to 30 minutes to perform the heat treatment for thin film separation. As a result, the first single crystal substrate 11 is broken at the ion implantation region 11a corresponding to the peak position of hydrogen ion implantation, and the upper thick portion 11c and the lower thin semiconductor layer 1 are separated.
1b (FIG. 1 (f)). Next, the temperature is lowered to remove the thick portion 11c (FIG. 1 (g)). Next, a second single crystal substrate 13 having a p ⁺ -type or p ⁺⁺ -type polysilicon layer 14, a p ⁻ -type polysilicon layer 16, an oxide film 12, and a semiconductor layer 11b sequentially laminated on the surface thereof is placed in an oxygen or nitrogen atmosphere. Heat treatment at 900-1200 ° C. for 30-120 minutes,
The semiconductor layer 11b and the second single crystal substrate 13 are p ⁺ -type or p-type
⁺⁺ type polysilicon layer 14, p ⁻ type polysilicon layer 1
6 and the oxide film 12 (FIG. 1)
(H)). Finally, the separation surface and the thick portion 1 of the semiconductor layer 11b
The separation surfaces 1c are polished (touch polished) and smoothed (FIGS. 1 (i) and 1 (j)). Thereby, the second single crystal substrate 13 becomes an SOI substrate, and the thick portion 11
c can be used again as a new semiconductor substrate in the manufacture of an SOI substrate.

As shown in FIG. 2, in order to manufacture an SOI substrate according to a second embodiment of the present invention, the same steps as those of the first embodiment based on FIG. 1 are repeated to form a p-type first single crystal. An oxide film 12 is formed on the surface of a silicon substrate 11 (see FIG. 2).
(A)). Next, as in the case of the first embodiment, the oxide film 12 is formed.
Hydrogen ions are implanted from the surface of the first single-crystal substrate 11 having an ion implantation region 11a inside the substrate 11 (FIG. 2B). Next, a p-type second single-crystal silicon substrate 13 having the same surface area as the first single-crystal silicon substrate 11 and serving as a support substrate is prepared.
3 is ion-implanted from the surface of
A phosphorus injection layer 13a is formed inside (FIG. 2C). Next, in order to increase the bonding strength between the first substrate 11 and the second substrate 13, the surface of the second substrate 13 is polished after phosphorus implantation to reduce the micro roughness of the substrate surface to about a polished wafer. preferable. Next, the first single crystal substrate 1
After cleaning the first and second single crystal substrates 13 respectively, the second single crystal substrate 13 is placed on the first single crystal substrate 11 via the oxide film 12.
Are overlapped and adhered (FIG. 2D). Then the first
While the single crystal substrate 11 is kept in close contact with the second single crystal substrate 13, the same thin film separation heat treatment as in the first embodiment is performed. As a result, the first single crystal substrate 11 is broken at the ion implantation region 11a and separated into an upper thick portion 11c and a lower thin semiconductor layer 11b (FIG. 2E). Next, the temperature is lowered and the thick portion 11
c (FIG. 2 (f)), and the second single crystal substrate 13 on which the oxide film 12 and the semiconductor layer 11b are sequentially laminated is placed on the first single crystal substrate 13.
The semiconductor layer 11b and the second single crystal substrate 13 are firmly bonded to each other through the oxide film 12 by performing a heat treatment in the same manner as in the embodiment (FIG. 2G). Finally, the separation surface of the semiconductor layer 11b and the separation surface of the thick portion 11c are polished and smoothed, respectively (FIGS. 2 (h) and 2 (i)). Thus, an SOI substrate including the second single crystal substrate 13 on which the oxide film 12 and the semiconductor layer 11b are sequentially stacked is obtained (FIG. 2H).

As shown in FIG. 3, in order to manufacture an SOI substrate according to a third embodiment of the present invention, the same steps as those of the first embodiment based on FIG. 1 are repeated to form a p-type first single crystal. An oxide film 12 is formed on the surface of a silicon substrate 11 (FIG. 3)
(A)). Next, as in the case of the first embodiment, hydrogen ions are implanted from the surface of the first single crystal substrate 11 having the oxide film 12 to form an ion implantation region 11a inside the substrate 11 (FIG. 3B). Next, a p-type second single-crystal silicon substrate 13 having the same surface area as the first single-crystal silicon substrate 11 and serving as a support substrate is prepared.
3 is ion-implanted from the surface of
A phosphorus injection layer 13a is formed inside (FIG. 3C). Next, a p ⁻ type polysilicon layer 16 is formed on the surface of the second single crystal substrate 13 on which the phosphorus implantation layer 13a is formed (FIG. 3).
(D)). The p ^- type polysilicon layer 16 has a thickness of 0.5 to
It is formed to have a thickness of 3 μm, preferably 0.5 to 2 μm. The boron concentration of the p ⁻ type polysilicon layer 16 is preferably equal to that of the first single crystal substrate 11. Next, the p ⁻ type polysilicon layer 16 is mirror-polished and flattened. Next, after cleaning the first single crystal substrate 11 and the second single crystal substrate 13 respectively, the second single crystal substrate 13 is placed on the first single crystal substrate 11 so that the p ⁻ type polysilicon layer 16 is in close contact with the oxide film 12. And put them together (Fig. 3
(E)). Next, a thin film separation heat treatment similar to that of the first embodiment is performed while the first single crystal substrate 11 is kept in close contact with the second single crystal substrate 13. As a result, the first single crystal substrate 11 is broken at the ion implantation region 11a and separated into an upper thick portion 11c and a lower thin semiconductor layer 11b (FIG. 3F). Next, the temperature is lowered to remove the thick portion 11c (FIG. 3 (g)), and the second single crystal substrate 13 on which the p ^- type polysilicon layer 16, the oxide film 12, and the semiconductor layer 11b are sequentially laminated is removed. The semiconductor layer 11b and the second single-crystal substrate 13 are subjected to a heat treatment in the same manner as in the first embodiment to form the oxide film 12 and the p ^- type polysilicon layer 16
(FIG. 3 (h)). Finally, the separation surface of the semiconductor layer 11b and the separation surface of the thick portion 11c are respectively polished and smoothed (FIG. 3 (i) and FIG.
(J)). As a result, the p ^- type polysilicon layer 1
6. An SOI substrate including a second single crystal substrate 13 in which an oxide film 12 and a semiconductor layer 11b are sequentially stacked is obtained (FIG. 3).
(I)).

[0010]

EXAMPLES Next, examples of the present invention will be described together with comparative examples in order to show specific embodiments of the present invention. <Example 1> As shown in FIG. 1A, an oxide film 12 having a thickness of 400 nm was formed on the surface of a p-type single crystal silicon substrate 11 by thermal oxidation. Next, a voltage of 70 keV was applied to the single crystal silicon substrate 11 to convert hydrogen ions into 7 × 10 ¹⁶ /
Ion implantation was performed at a dose of cm ² to form an ion implantation region 11a inside the single crystal substrate 11 (FIG. 1B). Next, a p-type second single-crystal silicon substrate 13 serving as a support substrate having the same surface area as the single-crystal substrate 11 is prepared, and a 1 μm-thick p ⁺ -type or p-type ^{A ++} type polysilicon layer 14 was formed (FIG. 1C). Next, a 1 μm thick p ⁻ type polysilicon layer 16 is formed on the p ⁺ type or p ⁺⁺ type polysilicon layer 14.
Was formed (FIG. 1D). Next, the p ^- type polysilicon layer 16 was mirror-polished and flattened. Next, after cleaning the first single crystal substrate 11 and the second single crystal substrate 13 with the SC1 cleaning liquid, the p ⁻ type polysilicon layer 1 is formed on the oxide film 12.
The second single crystal substrate 13 was superimposed on the first single crystal substrate 11 so that the substrates 6 were in close contact with each other (FIG. 1E). Next, a heat treatment was performed at a temperature of 600 ° C. for 30 minutes in a nitrogen atmosphere while keeping the first single crystal substrate 11 in close contact with the second single crystal substrate 13. As a result, the first single crystal substrate 11 was broken at the ion-implanted region 11a and separated into an upper thick portion 11c and a lower thin semiconductor layer 11b (FIG. 1 (f)). Next, the temperature is lowered to remove the thick portion 11c (FIG. 1 (g)), and the p ⁺ type or p ⁺⁺ type polysilicon layer 14, the p ⁻ type polysilicon layer 16, the oxide film 12, and the The second single crystal substrate 13 on which the semiconductor layers 11b were sequentially laminated was heat-treated at 1100 ° C. for 2 hours in a nitrogen atmosphere (FIG. 1 (h)). Finally, the separation surface of the semiconductor layer 11b was polished and smoothed to obtain a first embodiment.
Was manufactured (FIG. 1 (i)).

<Embodiment 2> As shown in FIGS. 2A and 2B, the same steps as those of Embodiment 1 are repeated to form a p-type first film having an oxide film 12 with a thickness of 400 nm on its surface. An ion implanted region 11a was formed inside the single crystal silicon substrate 11. Next, a p-type second single-crystal silicon substrate 13 having the same surface area as the first single-crystal substrate 11 and serving as a support substrate is prepared, and phosphorus is ion-implanted from the surface of the p-type second single-crystal substrate 13. The phosphorus injection layer 13 inside the second single crystal substrate 13
a was formed (FIG. 2C). Next, the first substrate 11 and the second
After phosphorus was injected, the surface of the second substrate 13 was polished to increase the bonding strength of the substrate 13. Next, after cleaning the first single crystal substrate 11 and the second single crystal substrate 13 with the SC1 cleaning liquid, the second single crystal substrate 13 is overlapped on the first single crystal substrate 11 with the oxide film 12 therebetween and adhered thereto ( FIG.
(D)). Then, the first single crystal substrate 11 is kept in contact with the second single crystal silicon substrate 13 at 600 ° C. in a nitrogen atmosphere.
At 30 ° C. for 30 minutes. As a result, the first single crystal substrate 11 was broken at the ion-implanted region 11a and separated into an upper thick portion 11c and a lower thin semiconductor layer 11b (FIG. 2E). Next, the temperature is lowered to remove the thick portion 11c (FIG. 2 (f)), and the oxide film 12 and the semiconductor layer 1 are formed on the surface.
The second single-crystal silicon substrate 13 on which 1b was sequentially laminated was heat-treated at 1100 ° C. for 2 hours in a nitrogen atmosphere (FIG. 2G). Finally, the separation surface of the semiconductor layer 11b was polished and smoothed to manufacture the SOI substrate of Example 2 (FIG. 2).
(H)).

<Embodiment 3> As shown in FIGS. 3A and 3B, the same steps as those of Embodiment 1 are repeated to form a p-type first film having a 400 nm-thickness oxide film 12 on its surface. An ion implanted region 11a was formed inside the single crystal silicon substrate 11. Next, a p-type second single-crystal silicon substrate 1 having the same surface area as the first single-crystal silicon substrate 11 and serving as a support substrate
3 was prepared, and phosphorus was ion-implanted from the surface of the p-type second single-crystal substrate 13 to form a phosphorus-implanted layer 13a inside the second single-crystal substrate 13 (FIG. 3C). Next, a thickness of 1 is formed on the surface of the second single crystal substrate 13 on which the phosphorus implantation layer 13a is formed.
A p ^- type polysilicon layer 16 of μm was formed (FIG. 3).
(D)). Next, the p − type polysilicon layer 16 was mirror-polished and flattened. Next, the first single-crystal substrate 11 and the second single-crystal substrate 13 are each washed with the SC1 cleaning liquid, and then the second single-crystal substrate 11 is attached to the first single-crystal substrate 11 such that the p ⁻ type polysilicon layer 16 is in close contact with the oxide film 12. The crystalline silicon substrate 13 was overlapped and adhered (FIG. 3E). Next, a heat treatment was performed at a temperature of 600 ° C. for 30 minutes in a nitrogen atmosphere while keeping the first single crystal substrate 11 in close contact with the second single crystal substrate 13. As a result, the first single crystal substrate 11 is
It was split at 1a and separated into an upper thick portion 11c and a lower thin semiconductor layer 11b (FIG. 3 (f)). Next, the temperature was lowered to remove the thick portion 11c (FIG. 3 (g)), and p
^- type polysilicon layer 16, oxide film 12 and the semiconductor layer 1
The second single crystal substrate 13 on which 1b was sequentially laminated was heat-treated at 1100 ° C. for 2 hours in a nitrogen atmosphere (FIG. 3).
(H)). Finally, the separation surface of the semiconductor layer 11b was polished and smoothed to manufacture the SOI substrate of Example 3 (FIG. 3).
(I)).

Comparative Example 1 A p ⁺ -type or p ⁺⁺ -type polysilicon layer 14 and a p ^-- type polysilicon layer 16 are formed on the surface of a p-type second single-crystal silicon substrate 13 serving as a support substrate. An SOI substrate of Comparative Example 1 was manufactured by substantially repeating the method of Example 1 except that no SOI substrate was provided.

<Comparative Evaluation> In each of the SOI substrates of Example 1, Example 2, Example 3, and Comparative Example 1, 10
The substrate surface was forcibly contaminated by a spin coating method using a copper standard solution of 00 ppm, and 900 ppm in a nitrogen atmosphere.
After heat treatment at 1 ° C. for 1 hour, the copper concentration (atoms / cm ³ ) in the semiconductor layer 11b was examined by an atomic absorption method.
FIG. 4 shows the results.

As is apparent from FIG.
The copper concentration (atoms / cm ³ ) in the OI layer is lower than that in Comparative Example 1. This indicates that the semiconductor layers 11b are less likely to be contaminated with heavy metal impurities than the SOI substrates of Comparative Example 1 because the SOI substrates of Examples 1 to 3 have a large gettering ability.

[0016]

As described above, according to the present invention, in an SOI substrate in which a semiconductor layer is overlaid on a semiconductor substrate via an oxide film, one side of a p-type single crystal silicon substrate serving as a semiconductor substrate is provided. A p ⁺ -type or p ⁺⁺ -type polysilicon layer, and a p ^-- type polysilicon layer is formed on the polysilicon layer, or from the surface of a p-type single-crystal silicon substrate serving as a support substrate. Since a phosphorus-implanted layer is formed inside the substrate by ion-implanting phosphorus or a p ^- type polysilicon layer is formed on the surface of the support substrate on which the phosphorus-implanted layer is formed, the semiconductor layer is be contaminated by heavy metal impurities during the device process, the p ^- capture and p ⁺ -type or p ⁺⁺ type of heavy metal impurities in the semiconductor layer acts polysilicon layer or the phosphorus injection layer as a gettering layer And then As a result, even if the heat treatment proceeds, the silicon layer is not contaminated with heavy metal impurities, and deterioration of the quality of the SOI substrate can be prevented.

[Brief description of the drawings]

FIG. 1 is a view showing a method for manufacturing a first SOI substrate according to an embodiment of the present invention in the order of steps;

FIG. 2 is a diagram showing a method for manufacturing a second SOI substrate according to the embodiment of the present invention in the order of steps.

FIG. 3 is a diagram showing a method for manufacturing a third SOI substrate according to the embodiment of the present invention in the order of steps.

FIG. 4 is a view showing the copper concentration in a semiconductor layer 11b in the SOI substrates of Examples 1 to 3 and Comparative Example 1.

[Explanation of symbols]

Reference Signs List 11 p-type first silicon substrate 11 a ion-implanted region 11 b silicon layer 11 c thick portion 12 oxide film 13 p-type second silicon substrate 13 a phosphorus-implanted layer 14 p ⁺ -type or p ⁺⁺ -type polysilicon layer 16 p ^-- type Polysilicon layer

Claims (3)

[Claims] Forming an oxide film on a surface of a p-type first silicon substrate; implanting hydrogen ions from a surface of the first silicon substrate to form the first silicon substrate; Forming a hydrogen ion implanted region (11a) inside the substrate (11), forming a p-type second silicon substrate (13) serving as a support substrate on one side of the substrate;
Of ⁺ type or p ⁺⁺ type forming polysilicon layer (14), p on the p ⁺ -type or p ⁺⁺ type polysilicon layer (14) of the second silicon substrate (13) ^- of the type forming a polysilicon layer (16), wherein the p ^- type polysilicon layer (16) wherein p is mirror polished to a step of mirror polishing, the oxide film (12) ^- type polysilicon layer (16) Superimposing the second silicon substrate (13) on the first silicon substrate (11) so that the first silicon substrate (11) is in close contact with the first silicon substrate (11); and bringing the first silicon substrate (11) into close contact with the second silicon substrate (13). The first silicon substrate (11) is separated from the second silicon substrate (13) in the hydrogen ion implantation region (11a) by performing a heat treatment at a predetermined temperature while keeping the second silicon substrate (13).
Forming a silicon layer (11b) on the surface of the second silicon substrate, the second silicon substrate having a silicon layer (11b) on the surface
(13) a method of manufacturing an SOI substrate, further comprising a step of performing a heat treatment. 2. A step of forming an oxide film (12) on a surface of a p-type first silicon substrate (11); and implanting hydrogen ions from the surface of the first silicon substrate (11) to form the first silicon substrate. Forming a hydrogen ion-implanted region (11a) inside the substrate (11); and ion-implanting phosphorus from the surface of a p-type second silicon substrate (13) serving as a support substrate to form the second silicon substrate (13). A step of forming a phosphorus implantation layer (13a) therein; and a step of forming the second silicon substrate (13) on the first silicon substrate (11) such that a surface of the oxide film (12) into which the phosphorus is ion-implanted adheres. Superimposing the first silicon substrate (11) on the second silicon substrate (13) and performing a heat treatment at a predetermined temperature while keeping the first silicon substrate (11) in close contact with the second silicon substrate (13). In the region (11a), the second silicon substrate (13) is separated from the second silicon substrate (13).
Forming a silicon layer (11b) on the surface of the second silicon substrate, the second silicon substrate having a silicon layer (11b) on the surface
(13) a method of manufacturing an SOI substrate, further comprising a step of performing a heat treatment. 3. A step of forming an oxide film (12) on the surface of a p-type first silicon substrate (11); and implanting hydrogen ions from the surface of the first silicon substrate (11) to form the first silicon substrate. Forming a hydrogen ion-implanted region (11a) inside the substrate (11); and ion-implanting phosphorus from the surface of a p-type second silicon substrate (13) serving as a support substrate to form the second silicon substrate (13). Forming a phosphorus injection layer (13a) therein; and a second silicon substrate (13) having the phosphorus injection layer (13a) formed thereon
Type ^- forming type polysilicon layer (16), the p ^{- -} p on the surface of the p type and steps of the polysilicon layer (16) mirror-polishing, which were mirror-polished to said oxide film (12) Superposing the second silicon substrate (13) on the first silicon substrate (11) so that the polysilicon layer (16) is in close contact with the first silicon substrate (11); The first silicon substrate (11) is separated from the second silicon substrate (13) in the hydrogen ion implanted region (11a) by heat treatment at a predetermined temperature while being kept in close contact with the substrate (13). Board (13)
Forming a silicon layer (11b) on the surface of the second silicon substrate, the second silicon substrate having a silicon layer (11b) on the surface
(13) a method of manufacturing an SOI substrate, further comprising a step of performing a heat treatment.