JPH08321594A - Production of soi substrate - Google Patents

Abstract

PURPOSE: To suppress dislocation defect of an Si layer in the vicinity of surface of a substrate by implanting He ions, which do not react on silicon in the vacuum, into a silicon substrate to form a region damaged by ion implantation in the substrate and then subjecting the substrate to high temperature annealing in oxidizing atmosphere. CONSTITUTION: He ions, H ions, Ar ions or Si ions are implanted into a silicon substrate in the vacuum to form a region 12 damaged by ion implantation. In the region 12, a silicon atom is discharged from the lattice position to produce an interstitial silicon atom 14 and a hole 15 is formed at the lattice position. When the silicon substrate 11 is annealed at 1000-1400 deg.C in oxidizing atmosphere, oxygen atoms 16 are diffused through diffusion control into the substrate while oxidizing an Si layer on the surface of substrate to form an oxide layer 11c. He and the like does not react on silicon and discharged to the outside of substrate in the atmosphere and the diffused oxygen forms SiOx preferentially because of the holes 15 existing in the region 12 damaged by ion implantation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an SOI (Silicon-On-Insulator) substrate in which a silicon layer is formed on an insulating layer. For more details, SIMOX (Separation by
The present invention relates to a method for manufacturing an SOI substrate by Implanted Oxygen) technology.

[0002]

2. Description of the Related Art SOI substrates are used in future ultra-high integrated circuits (UL).
SI) has attracted attention as a substrate. This SOI substrate manufacturing method 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 its surface, and SIM.
OX method and the like. This SIMOX method is one of the methods of burying an insulating layer inside a silicon substrate. Specifically, after implanting high-concentration oxygen ions inside the silicon substrate,
In this method, an embedded silicon oxide layer is formed in a region of a predetermined depth from the surface of the silicon substrate by annealing at a high temperature, and the Si layer on the surface side is used as an active region. This SIM
In the OX method, oxygen is excessively ion-implanted into the silicon substrate at a time, so that silicon atoms at lattice positions are released to interstitial silicon atoms and vacancies are formed at lattice positions. Subsequently, high-temperature annealing treatment is performed to expand the volume of the silicon substrate to rearrange the implanted oxygen ions and interstitial silicon atoms to deposit a silicon oxide layer in the ion-implanted damaged region in an extremely short time. .

[0003]

However, the conventional S
In the IMOX method, excessive interstitial silicon atoms generate microdefects, and these microdefects tend to grow near the substrate surface during rearrangement by high-temperature annealing to easily form dislocation defects. Further, in the above method, since the atomic amount of oxygen to be ion-implanted is relatively large and therefore a high acceleration voltage is required, the oxygen concentration is likely to be widely distributed in the depth direction from the implanted substrate surface, and the substrate surface becomes rough. The boundary of the buried silicon oxide layer tended not to be steep. This tendency was remarkable especially when the buried silicon oxide layer was formed deeply from the substrate surface. In other words, in the case of oxygen ion implantation, the surface roughness of the SOI substrate is large,
In addition, the ion-implanted damaged region is apt to be widened, and it has been difficult to form a buried silicon oxide layer having a steep boundary in a predetermined depth region by annealing. Further, in the above method, when oxygen ion implantation is performed, F
Heavy metals such as e, Ni, Cu, Zn, and Cr easily infiltrate into the vicinity of the surface of the silicon substrate at high concentration as impurities. If these heavy metals are present in the Si layer in the active region of the substrate surface, there is a problem that the electrical characteristics of the device are greatly affected.

An object of the present invention is to add S in the active region of the substrate surface.
An object of the present invention is to provide a method for manufacturing an SOI substrate in which dislocation defects are hard to form in the i layer. Another object of the present invention is to provide an SOI substrate which has a relatively low accelerating voltage to reduce the substrate surface roughness and to form a buried silicon oxide layer having a sharp boundary and a small layer thickness in a predetermined depth region. It is to provide a manufacturing method. Still another object of the present invention is to provide a method for manufacturing an SOI substrate which can reduce heavy metals in the substrate.

[0005]

The invention according to claim 1 is
As shown in FIGS. 1A to 1D, a silicon substrate 1
Forming an ion-implanted damage region 12 inside the silicon substrate 11 by implanting at least He ions, H ions, Ar ions or Si ions in a vacuum in 1;
Silicon substrate 11 on which ion implantation damage region 12 is formed
Is annealed at a temperature of 1000 ° C. to 1400 ° C. in an oxidizing atmosphere to form a buried silicon oxide layer 13 in a region of a predetermined depth from the surface of the silicon substrate 11 to form a single crystal Si layer 11a on the surface of the substrate. The manufacturing method of the SOI substrate 10 including the steps.

When He ions, H ions, Ar ions or Si ions are implanted into the silicon substrate 11 shown in FIG. 1A in a vacuum, an ion implantation damage region 12 is formed as shown in FIG. 1B. In this ion-implanted damage region 12, silicon atoms at the lattice position are released to become interstitial silicon atoms 14 (indicated by * in the figure) and vacancies 15 (indicated by ○ in the figure) are formed at the lattice position. To be done. Subsequently, when the silicon substrate 11 is annealed at a temperature of 1000 ° C. to 1400 ° C. in an oxidizing atmosphere, oxygen atoms 16 (indicated by ● in the figure) are obtained as shown in FIGS. 1 (c) and 1 (d).
Oxide layer 11c by oxidizing the Si layer on the substrate surface
Is diffused inside the substrate while forming the film.
Since He and the like do not react with silicon, they are released to the outside of the substrate in the atmosphere. The diffused oxygen atoms preferentially form SiOx due to the existence of the holes 15 in the ion implantation damage region 12. Oxidation proceeds due to this diffusion control, so that interstitial silicon atoms are not abruptly generated, micro defects are hardly generated, and dislocation defects can be suppressed.

The invention according to claim 2 is shown in FIGS.
As shown in (e), the step of forming the ion-implanted damaged region 12 inside the silicon substrate 11 by implanting at least He ions or H ions into the silicon substrate 11 in a vacuum, and the ion-implanted damaged region 12 are formed. The silicon substrate 11 is annealed at a temperature of 800 ° C. to 1000 ° C., and He atoms or H atoms implanted in the ion-implanted damaged region 12 are released from the damaged region 12 to form the vacancy region 15.
And the silicon substrate 11 in which the hole regions 15 are formed in an oxidizing atmosphere at 1000 ° C. to 1400 ° C.
A step of annealing at a temperature of ° C to form a buried silicon oxide layer 13 in a region of a predetermined depth from the surface of the silicon substrate 11 and form a single crystal Si layer 11a on the surface of the silicon substrate. Is the way. According to this method, a silicon substrate on which Si atoms (s is surrounded by a circle in the drawing) are arranged is annealed at a temperature of 800 ° C. to 1000 ° C., so that He atoms or H atoms (h in the drawing, h Is surrounded by a circle), and oxygen atoms (indicated by a black circle in the figure) enter the vacancy region 15 generated by the intrusion by an annealing treatment in an oxidizing atmosphere to remove SiOx. Since it is formed, the buried silicon oxide layer can be formed more stably.

The invention according to claim 3 is shown in FIGS.
As shown in (e), a step of implanting at least He ions or H ions in the silicon substrate 21 in a vacuum to form the ion-implanted damaged region 22 inside the silicon substrate 21, and the ion-implanted damaged region 22 is formed. Annealing the silicon substrate 21 at a temperature of 800 to 1400 ° C. to release He atoms or H atoms implanted in the ion-implanted damage region 22 from this region 22 to form a vacancy region 23; 21 and a step of implanting oxygen ions into the inside to form the SiOx region 24 around the vacancy region 23, and the silicon substrate 2 on which the SiOx region 24 is formed.
1 is annealed at a temperature of 1000 ° C. to 1400 ° C. in an oxidizing atmosphere to form a buried silicon oxide layer 26 in a region of a predetermined depth from the surface of the silicon substrate 21 to form a single crystal Si layer 21a on the surface of the silicon substrate. A method of manufacturing the SOI substrate 20 including a step of forming. According to this method
Oxygen atoms (indicated by ● in the figure) enter the vacancy region 23 generated by the release of He atoms or H atoms (h is circled in the figure) out of the substrate by ion implantation and SiOx.
Therefore, the buried silicon oxide layer can be formed much more stably as compared with the invention according to claim 1 or 2.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the silicon substrate 11, after the buried silicon oxide layers 13, 26 are formed by annealing.
21 is a method for manufacturing an SOI substrate further including a step of polishing the surface. According to this method, the surface roughness of the substrate can be further reduced, and the single crystal Si layers 11a and 21a having smaller microroughness can be obtained. The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein when the ions to be implanted are He ions or H ions, the dose amount at the time of ion implantation is 1 × 10 ¹⁶ / cm ^2. ~ 5x
10 ¹⁷ / cm ² , acceleration voltage is 40 keV to 200 ke
This is a method for manufacturing an SOI substrate of V. The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the annealing treatment for forming the buried silicon oxide layers 13 and 26 is performed in an oxidizing atmosphere at 10 to 100 atm. This is a method of manufacturing an SOI substrate. According to this method, the buried silicon oxide layer can be formed more stably.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when the implanted ions are Ar ions or Si ions, Ar or Si is used.
Since the atomic weight of is larger than that of He, the dose amount during ion implantation is 1 × 10 ¹⁵ / cm ² to 1 × 10 ¹⁷ / cm ² depending on the depth from the surface of the buried silicon oxide layer,
The acceleration voltage at this time is 150 keV to 200 keV. The substrate temperature at the time of ion implantation of the present invention is 500 ° C. to 70 ° C.
0 ° C is preferable, and 600 ° C is more preferable. The annealing treatment is performed in an oxidizing atmosphere at a temperature range of 1000 ° C to 1400 ° C for 1 to 8 hours. This processing temperature is 1300 ℃
1400 degreeC is preferable and 1350 degreeC is more preferable.
The time is preferably 4 to 8 hours, more preferably about 6 hours. Examples of the oxidizing atmosphere include an oxygen atmosphere having a concentration of 10 to 100%, and a high-concentration oxygen atmosphere having a concentration close to 100% is preferable. Further, the atmosphere of the annealing treatment for releasing the He atoms or the H atoms injected into the ion-implanted damaged region from the damaged region to form the vacancy region is 0.5 to 3% O ₂ , and the remaining inert gas is mixed. A gas atmosphere is preferred. The small amount of oxygen is contained in order to prevent the surface of the substrate from being roughened. The surface of a silicon substrate is lightly polished by a silicon wafer polishing machine, a lens polishing machine, or the like.
In this polishing, the substrate surface has a thickness of 50 Å to 5 Å.
It is desirable to ablate to a depth of about 100 Å, preferably about 100 Å.

In particular, when the implanted ions are He ions or H ions, since the atomic weight of He and H is small, dislocation defects in the Si layer near the surface of the substrate are less likely to occur as compared with conventional oxygen ion implantation. The ion implantation damage region can be formed at a predetermined depth with an acceleration voltage lower than that of oxygen ions. Due to the low acceleration voltage, it becomes easy to form a buried silicon oxide layer having a sharp boundary and a small layer thickness in the ion-implanted damage region, and as a result, it becomes easy to control the precipitation of SiO ₂ . Further, during ion implantation, sputtering on the surface of the Si layer is reduced and the surface roughness of the substrate is reduced. At the same time, the sputtering of the inner wall of the device is significantly reduced, and the contamination of the substrate with heavy metals is reduced.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings together with comparative examples. Example 1 As shown in FIGS. 1A and 1B, He ions (He ⁺ ) were implanted into a predetermined region of a 625 μm thick silicon substrate 11 under the following conditions. Acceleration voltage: 40 keV Dose amount: 1.0 × 10 ¹⁷ / cm ² Substrate heating temperature: 600 ° C. By this ion implantation, an ion implantation damage region 12 of about 0.3 μm was formed from the surface of the silicon substrate 11. After the ion implantation, as shown in FIGS. 1C and 1D, the silicon substrate 11 is subjected to 1325 in an oxygen (100%) atmosphere.
Annealing treatment was performed at 8 ° C. for 8 hours to change the ion-implanted damaged region 12 into a buried silicon oxide layer 13 to obtain an SOI substrate 10. Reference numeral 11a denotes a Si layer on the front surface side of the substrate, and 11b denotes a Si layer on the back surface side of the substrate.

<Example 2> An SOI substrate was obtained in which the ion implantation damage region was replaced with a buried silicon oxide layer in the same manner as in Example 1 except that the acceleration voltage was set to 60 keV.

<Embodiment 3> The He ions (He) of Embodiment 1
Instead of ⁺ ), H ions (H ⁺ ) were implanted under the following conditions. Accelerating voltage: 40 keV Dose amount: 1 × 10 ¹⁷ / cm ² Substrate heating temperature: 600 ° C. About 0.5 from the surface of the silicon substrate by this ion implantation.
A μm ion-implanted damage region was formed. After the ion implantation, the silicon substrate on which the ion-implanted damaged region is formed is annealed at a high temperature in the same manner as in Example 1 to change the ion-implanted damaged region into a buried silicon oxide layer, and the SOI
A substrate was obtained.

<Embodiment 4> The He ion (He) of Embodiment 1
Instead of ⁺ ), Ar ions (Ar ⁺ ) were implanted under the following conditions. Accelerating voltage: 200 keV Dose amount: 5 × 10 ¹⁶ / cm ² Substrate heating temperature: 600 ° C. About 0.2 from the surface of the silicon substrate by this ion implantation.
A μm ion-implanted damage region was formed. After the ion implantation, the silicon substrate on which the ion-implanted damaged region is formed is annealed at a high temperature in the same manner as in Example 1 to change the ion-implanted damaged region into a buried silicon oxide layer, and the SOI
A substrate was obtained.

<Embodiment 5> The He ions (He) of Embodiment 1
Instead of ⁺ ), Si ions (Si ⁺ ) were implanted under the following conditions. Accelerating voltage: 200 keV Dose amount: 1 × 10 ¹⁷ / cm ² Substrate heating temperature: 600 ° C. About 0.3 from the surface of the silicon substrate by this ion implantation.
A μm ion-implanted damage region was formed. After the ion implantation, the silicon substrate on which the ion-implanted damaged region is formed is annealed at a high temperature in the same manner as in Example 1 to change the ion-implanted damaged region into a buried silicon oxide layer, and the SOI
A substrate was obtained.

Example 6 As shown in FIGS. 2A and 2B, He ions (He ⁺ ) were implanted into a predetermined region of a silicon substrate 11 having a thickness of 625 μm under the following conditions. Acceleration voltage: 40 keV Dose amount: 1 × 10 ¹⁷ / cm ² Substrate heating temperature: 600 ° C. By this ion implantation, an ion implantation damage region 12 of about 0.3 μm was formed from the surface of the silicon substrate 11. After ion implantation, the silicon substrate 11 is annealed at 1000 ° C. for 1 hour in a mixed gas atmosphere of Ar 99% and O ₂ 1% as shown in FIGS. He atoms injected into the damaged region 1
2 to form a vacancy region 15, and this vacancy region 1
The silicon substrate 11 on which No. 5 is formed is annealed at a temperature of 1325 ° C. in an oxygen (100%) atmosphere to convert the surface of the silicon substrate 11 into a buried silicon oxide layer 13 in a region of a predetermined depth. Obtained. Reference numeral 11a denotes a Si layer on the front surface side of the substrate, and 11b denotes a Si layer on the back surface side of the substrate.

<Example 7> An SOI substrate was obtained in which the vacancy region was replaced with a buried silicon oxide layer in the same manner as in Example 6 except that the acceleration voltage was set to 60 keV.

<Embodiment 8> The He ions (He) of Embodiment 6
Instead of ⁺ ), H ions (H ⁺ ) were implanted under the following conditions. Accelerating voltage: 40 keV Dose amount: 1 × 10 ¹⁷ / cm ² Substrate heating temperature: 600 ° C. About 0.5 from the surface of the silicon substrate by this ion implantation.
A μm ion-implanted damage region was formed. After the ion implantation, the silicon substrate on which the ion implantation damaged region was formed was treated in the same manner as in Example 6 to obtain an SOI substrate.

Comparative Example 1 Oxygen ions (O ⁺ ) were implanted under the following conditions into a predetermined region (for example, a region of about 0.4 μm from the substrate surface) of a 625 μm thick silicon substrate. Accelerating voltage: 120 keV Dose amount: 0.4 × 10 ¹⁸ / cm ² Substrate heating temperature: 600 ° C. After implanting oxygen ions into the silicon substrate 11, Ar 97%
Then, the silicon substrate was annealed at 1325 ° C. for 6 hours in a mixed gas atmosphere of O ₂ 3% to obtain an SOI substrate.

Example 9 As shown in FIGS. 3A and 3B, He ions (He ⁺ ) were implanted into a predetermined region of a silicon substrate 21 having a thickness of 625 μm under the following conditions. Accelerating voltage: 40 keV Dose amount: 1 × 10 ¹⁷ / cm ² Substrate heating temperature: 600 ° C. By this ion implantation, an ion implantation damage region 22 of about 0.3 μm was formed from the surface of the silicon substrate 21. After the ion implantation, the silicon substrate 21 is annealed at 1325 ° C. for 2 hours in a mixed gas atmosphere of 99% Ar and 1% O ₂ as shown in FIGS. He atoms injected into the damaged region 2
2 to form void regions 23.

Subsequently, oxygen ions (O ⁺ ) were implanted into the silicon substrate 21 under the following conditions. Accelerating voltage: 150 keV Dose amount: 4 × 10 ¹⁷ / cm ² Substrate heating temperature: 600 ° C. After implanting oxygen ions into the silicon substrate 21, Ar 99%
Then, the silicon substrate was annealed at 1360 ° C. for 4 hours in a mixed gas atmosphere of O ₂ 1% to obtain an SOI substrate.

<Embodiment 10> A silicon substrate was used except that the silicon substrate 21 having the ion-implanted damaged region 22 was annealed at 1000 ° C. for 2 hours in a mixed gas atmosphere of Ar 99% and O ₂ 1%. The same process as in Example 9 was carried out to obtain an SOI substrate.

<Evaluation> (a) Defect Density The dislocation defect density in the Si layer on the substrate surface of each of the SOI substrates of Examples 1 to 10 and Comparative Example 1 was measured. The dislocation defect density was obtained by etching the SOI substrate with a solution containing chromium oxide and observing the dislocation defects enlarged by etching with an electron microscope. Table 1 shows the results.

[0025]

[Table 1]

As is clear from Table 1, compared with the dislocation defect density of Comparative Example 1 which was annealed at high temperature in a mixed gas atmosphere of Ar and O ₂ after oxygen ion implantation, He, H, Ar, which do not react with Si, The dislocation defect densities of Examples 1 to 10 which were annealed at high temperature in an O ₂ atmosphere or a mixed gas atmosphere of Ar and O ₂ after implanting Si ions were all low. Particularly, the dislocation defect densities of Examples 1 to 3 and 6 to 10 in which the light elements He and H were ion-implanted were extremely low.

(B) Surface Roughness of SOI Substrate Each SOI of Example 1, Example 6, Example 9 and Comparative Example 1
The surface roughness in a 2 μm × 2 μm region on the substrate surface was measured using an atomic force microscope. The results are shown in Table 2. In Table 2, Ra is the average roughness of the surface roughness, Rm
ax means maximum height, and Rz means ten-point average roughness.

[0028]

[Table 2]

As is clear from Table 2, the SO of Comparative Example 1
The surface roughness of the I substrate was remarkably large, whereas the surface roughness of the SOI substrates of Example 1, Example 6 and Example 9 was small, and was about the initial silicon wafer.

(C) Heavy Metal Concentration The concentration of heavy metal in the surface Si layer of each SOI substrate after the annealing treatment of Example 1 and Comparative Example 1 was measured by the atomic absorption method. Table 3 shows the results.

[0031]

[Table 3]

As is clear from Table 3, the SO of Comparative Example 1
Contamination of heavy metals such as Fe, Ni, and Cu was particularly remarkable in the surface Si layer of the I substrate, whereas the concentration of these heavy metals was reduced in the surface Si layer of Example 1.

(D) Boundary of buried silicon oxide layer Example 1, Example 2, Example 6, Example 7, Example 9,
The cross sections of the SOI substrates of Example 10 and Comparative Example 1 were observed with a transmission electron microscope, and the steepness of the boundary of the embedded silicon oxide layer was observed. As a result, the boundary of the buried silicon oxide layer of Comparative Example 1 is not so steep, while the boundary of Example 1,
The boundaries of the buried silicon oxide layers 2, 6, 7, 9, 10 were steep. In particular, the buried silicon oxide layers of Example 1 and Example 6 had an acceleration voltage lower than that of Examples 2 and 7, respectively, and thus were steeper than those of Examples 2 and 7.

[0034]

As described above, according to the method for manufacturing an SOI substrate of the present invention, He ions or the like that do not react with silicon in a vacuum are implanted into a silicon substrate to form an ion implantation damaged region inside the substrate. After that, the substrate is annealed at a high temperature in an oxidizing atmosphere, or another anneal process is performed before the high temperature anneal to form a vacancy region, or after the vacancy region is formed. By implanting oxygen ions, oxygen atoms diffuse into the substrate by diffusion control, and the presence of the vacancy formed by the ion implantation can preferentially form a buried silicon oxide layer in the ion implantation damaged region. . While conventional oxygen ion implantation forms a buried silicon oxide layer in a very short time and abruptly generates interstitial silicon atoms, this oxidation progresses in a diffusion-controlled manner, so that abrupt changes in interstitial silicon atoms occur. There is no occurrence, and dislocation defects can be suppressed. In particular, when the implanted ions are He ions or ions of an element having a small atomic weight such as H ions, dislocation defects in the Si layer near the surface of the substrate are more difficult to occur, and the acceleration voltage is lower than that of oxygen ions. The ion implantation damage region can be formed at a predetermined depth. In other words, even with the same acceleration voltage, the buried silicon oxide layer can be formed in a deeper region by the ion implantation of the present invention as compared with the oxygen ion implantation.
This low accelerating voltage facilitates formation of a buried silicon oxide layer having a sharp boundary and a small layer thickness, and facilitates control of precipitation of SiO ₂ . Further, during ion implantation, sputtering on the surface of the Si layer is reduced and the surface roughness of the substrate is reduced. At the same time, the sputtering of the inner wall of the device is significantly reduced, and the contamination of the substrate with heavy metals is reduced.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a method of manufacturing an SOI substrate according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a method for manufacturing an SOI substrate according to another embodiment of the present invention.

FIG. 3 is a diagram schematically showing a method of manufacturing an SOI substrate according to still another embodiment of the present invention.

[Explanation of symbols]

 10, 20 SOI substrate 11, 21 Silicon substrate 11a, 21a Si layer on substrate surface 12,22 Ion implantation damage region 13,26 Buried silicon oxide layer 14 Interstitial silicon atom 15,23 Vacancy region 16,25 Oxygen atom 24 SiOx region

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 21/76 R

Claims (6)

[Claims] 1. A step of forming an ion-implanted damaged region (12) inside the silicon substrate (11) by implanting at least He ions, H ions, Ar ions or Si ions into the silicon substrate (11) in a vacuum. And a silicon substrate on which the ion implantation damage region (12) is formed
(11) is annealed at a temperature of 1000 ° C. to 1400 ° C. in an oxidizing atmosphere to form a buried silicon oxide layer (13) in a region of a predetermined depth from the surface of the silicon substrate (11) to form the surface of the substrate. And a step of forming a single crystal Si layer (11a) on the substrate. 2. A step of forming an ion-implanted damaged region (12) inside the silicon substrate (11) by implanting at least He ions or H ions into the silicon substrate (11) in a vacuum, and the ion-implanted damage. Silicon substrate with regions (12) formed
A step of annealing (11) at a temperature of 800 ° C. to 1000 ° C. to release He atoms or H atoms injected into the region (12) from the region (12) to form a vacancy region (15). And annealing the silicon substrate (11) in which the void regions (15) are formed at a temperature of 1000 ° C. to 1400 ° C. in an oxidizing atmosphere to form a region having a predetermined depth from the surface of the silicon substrate (11). And a step of forming a buried silicon oxide layer (13) on the surface of the substrate to form a single crystal Si layer (11a) on the surface of the substrate. 3. A step of forming an ion implantation damage region (22) inside the silicon substrate (21) by implanting at least He ions or H ions into the silicon substrate (21) in a vacuum, and the ion implantation damage. Silicon substrate with regions (22) formed
(21) is annealed at a temperature of 800 to 1400 ° C., and He atoms or H atoms injected into the region (22) are added to the region.
(22) to form vacancy regions (23), and oxygen ions are implanted into the silicon substrate (21) to form SiOx regions (24) around the vacancy regions (23). And a step of annealing the silicon substrate (21) on which the SiOx region (24) is formed at a temperature of 1000 ° C. to 1400 ° C. in an oxidizing atmosphere to obtain a predetermined depth from the surface of the silicon substrate (21). A step of forming a buried silicon oxide layer (26) in the region and forming a single crystal Si layer (21a) on the surface of the substrate. 4. An embedded silicon oxide layer (1
The method of manufacturing an SOI substrate according to claim 1, further comprising a step of polishing the surface of the silicon substrate (11, 21) after forming (3, 26). 5. When the implanted ions are He ions or H ions, the dose amount at the time of implanting the ions is 1 × 10.
¹⁶ / cm ^{2 to} 5 × 10 ¹⁷ / cm ² , acceleration voltage is 40 ke
It is V-200 keV, S in any one of Claims 1-4.
Manufacturing method of OI substrate. 6. The SOI according to claim 1, wherein the annealing treatment for forming the buried silicon oxide layer (13, 26) is performed in an oxidizing atmosphere under 10 to 100 atm.
Substrate manufacturing method.