Ge-CONTAINING SUBSTRATE AND METHOD FOR MANUFACTURING THE SAME

Abstract

To provide a high-quality Ge-containing substrate that has a Si substrate and a Ge-containing layer and is efficiently manufactured.SOLUTION: A Ge-containing substrate includes: a carbon-doped silicon epitaxial layer on a silicon substrate; and a SixGe1-x layer (0≤x<1) on the silicon epitaxial layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a Ge-containing substrate and a method for manufacturing a Ge-containing substrate. [Background technology]

[0002] SiGe and Ge are materials widely used in various devices such as electronic, optical, and RF devices. In particular, SiGe is a material that plays an important role in the manufacturing processes of GAA (Gate All Around) and CFET (Complementary Field Effect Transistor), which stacks NMOS and CMOS, proposed for next-generation semiconductors, replacing the fin structure currently used in logic ICs (Non-Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-180285 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-363592 [Non-patent literature]

[0004] [Non-Patent Document 1] The 1st Workshop of the Industry-Academia Collaboration Committee on Crystal Growth, Processing, and Evaluation of Semiconductors of the Japan Society of Applied Physics: "Crystal Technology Supporting the Revival of Semiconductors" [Non-patent document 2] Yonenaga, "Growth of high-quality SiGe crystals and elucidation of their fundamental properties," Material, 47(1), 3(2008) [Non-patent document 3] Sato, "Fundamentals and Challenges of Heteroepitaxy: 1st Workshop on 3C-SiC Technology for IoT in Harsh Environments" (2019) [Non-patent document 4] Wong, LH “Strain relaxation in SiGe / Si heteroepitaxy.” Doctoral thesis, Nanyang Technological University, Singapore, (2007). [Non-Patent Document 5] EAFitgerald, et.al., “Totally relaxed GexSi1-x layers with low threading dislocation densities grows on Si substrares”, App. Phys. Lett., 59, 811 (1991). [Non-patent document 6] FKLeGeues, et.al., “Mechanism and conditions for anomalous strain relaxation in graded thin films and superlattices”, App.Phys.Lett., 71, 4230 (1992). [Non-Patent Document 7] T.Taniguchi,et.al.,Abst.of SAP Spring Meeting.,17a-F102-9(2018). [Non-patent document 8] T.Taniguchi,et.al.,Abst.of JSAP Autumn Meeting.,20p-234-10(2018). Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the equilibrium phase diagram, the liquidus and solidus of SiGe are far apart, and the distribution coefficient is 2 to 5, which is greater than 1, making it known that it is prone to polycrystallization. Even if single crystals can be grown, the growth rate is slow and it is difficult to grow them consistently (Non-Patent Document 2).

[0006] Therefore, for semiconductor devices, SiGe is grown on Si substrates, sometimes referred to as virtual SiGe substrates. In this SiGe growth (heteroepitaxial), the key issue is how to mitigate the difference in lattice constants between Si and Ge. The lattice constant of Si crystals is 0.5431 nm, while that of Ge crystals is 0.56754 nm, resulting in a difference of approximately 4.5%. To mitigate this difference in lattice constants, SiGe uses a SiGe alloy. If the Ge composition ratio is x, the lattice constant of the SiGe alloy is 0.5431 nm + x × 0.02 nm + x squared × 0.0027 nm. For example, if x is 0.3, the lattice constant is 0.5493 ​​nm, resulting in a minimal lattice mismatch of 0.14%. This lattice mismatch can cause dislocations and defects to develop in the subsequently grown epitaxial layer, resulting in degradation of quality. However, it is believed that there is a critical thickness, and even if there is lattice mismatch, defects will not occur unless the critical thickness is exceeded (Non-Patent Document 3).

[0007] Therefore, various intermediate layers have been proposed that utilize this critical thickness to form a buffer layer. For example, there is a method in which the Ge concentration is varied from the silicon substrate to a SiGe layer with a predetermined Ge concentration, which is called a graded buffer layer (Non-Patent Documents 4, 5, 6). Another method has been proposed, which involves stacking multiple layers with thicknesses below the critical thickness, called a superlattice buffer layer (Non-Patent Documents 6, 7, 8).

[0008] In addition to these techniques, Patent Document 1 also describes a method for manufacturing a strain-relaxed SiGe-on-SOI substrate, in which a SiGe layer is epitaxially grown on the Si layer of an SOI substrate using a low-pressure CVD apparatus to provide a strained SiGe layer that does not have periodic crosshatch-shaped surface irregularities, and the SiGe-on-SOI substrate having the strained SiGe layer is thermally oxidized to increase the Ge concentration and relax the strain.

[0009] Patent Document 2 also describes a method for forming a high-quality, fully lattice-relaxed SiGe-on-insulator substrate material using SIMOX and Ge interdiffusion, in which ions are first implanted into a Si-containing substrate, and the implantation-rich region has a sufficient ion concentration so that a barrier layer that prevents Ge diffusion is formed during annealing at high temperature. Next, a Ge-containing layer is formed on the surface of the Si-containing substrate, and then a heating step is performed at a temperature that allows the formation of the barrier layer and Ge interdiffusion, thereby forming a fully lattice-relaxed single-crystal SiGe layer on the barrier layer.

[0010] As described above, various methods have been investigated, but the methods described in Patent Documents 1 and 2 in particular are premised on the bonding and peeling process, which inevitably leads to defects in this process and also increases the number of steps in the substrate manufacturing process.

[0011] The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-quality Ge-containing substrate that has a Si substrate and a Ge-containing layer and is efficiently manufactured.

[0012] The present invention has also been made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a Ge-containing substrate by forming a Ge-containing layer on a Si substrate, which is a method for efficiently manufacturing a high-quality Ge-containing substrate. [Means for solving the problem]

[0013] The present invention has been made to achieve the above object, and provides a method for manufacturing a silicon epitaxial layer doped with carbon on a silicon substrate, and a method for manufacturing a silicon epitaxial layer doped with carbon on the silicon epitaxial layer. x Ge 1-x A Ge-containing substrate is provided, characterized by having a layer (0≦x<1).

[0014] Such a Ge-containing substrate has an intermediate layer, a carbon-doped silicon layer formed by epitaxial growth, and is an efficiently produced high-quality Ge-containing substrate.

[0015] At this time, the carbon concentration of the silicon epitaxial layer is 1×10 20 ~4×10 21 atoms / cm 3 It can be assumed that:

[0016] This results in a better silicon epitaxial layer with fewer defects.

[0017] At this time, the carbon concentration of the silicon epitaxial layer is 4×10 20 ~8×10 20 atoms / cm 3 It can be assumed that:

[0018] This results in a better silicon epitaxial layer with fewer defects.

[0019] At this time, the Si x Ge 1-x The layer may be a SiGe layer.

[0020] This allows the Ge-containing substrate to have a SiGe layer.

[0021] At this time, the Si x Ge 1-x The layer may be a Ge layer.

[0022] This allows the Ge-containing substrate to have a Ge layer.

[0023] The present invention has also been made to achieve the above object, and provides a method for epitaxially growing a carbon-doped silicon layer on a silicon substrate, and depositing a Si layer on the carbon-doped silicon layer. x Ge 1-x A method for producing a Ge-containing substrate is provided, characterized by growing a layer (0≦x<1).

[0024] According to such a method for producing a Ge-containing substrate, a high-quality Ge-containing substrate can be efficiently produced by forming an intermediate layer of a silicon layer doped with carbon by epitaxial growth.

[0025] At this time, the carbon concentration of the carbon-doped silicon layer is set to 1×10 20 ~4×10 21 atoms / cm 3 It can be said that:

[0026] This allows the carbon-doped silicon layer to be formed in a good condition with fewer defects.

[0027] At this time, the carbon concentration of the carbon-doped silicon layer is set to 4×10 20 ~8×10 20 atoms / cm 3 It can be said that:

[0028] This allows the carbon-doped silicon layer to be formed in a good condition with fewer defects.

[0029] At this time, the carbon-doped silicon layer can be epitaxially grown at 700 to 900°C.

[0030] This allows the carbon-doped silicon layer to be formed in a good condition with fewer defects.

[0031] At this time, the carbon-doped silicon layer can be epitaxially grown at 730 to 750°C.

[0032] This allows the carbon-doped silicon layer to be formed in a good condition with fewer defects.

[0033] At this time, the Si x Ge 1-x The layer may be a SiGe layer.

[0034] This results in a Ge-containing substrate having a SiGe layer.

[0035] At this time, the Si x Ge 1-x The layer may be a Ge layer.

[0036] This results in a Ge-containing substrate having a Ge layer. [Effects of the Invention]

[0037] As described above, the Ge-containing substrate of the present invention is an efficiently produced, high-quality Ge-containing substrate having an intermediate layer formed by epitaxial growth of a carbon-doped silicon layer. Furthermore, according to the method for producing a Ge-containing substrate of the present invention, a carbon-doped silicon layer is formed as an intermediate layer by epitaxial growth, thereby making it possible to efficiently produce a high-quality Ge-containing substrate. [Brief explanation of the drawings]

[0038] [Figure 1] 1 shows a schematic diagram of an example of a Ge-containing substrate according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention will be described in detail below, but the present invention is not limited thereto.

[0040] As described above, there has been a demand for a high-quality Ge-containing substrate that is efficiently produced and has a silicon single crystal substrate (also referred to as a silicon substrate or an Si substrate) and a Ge-containing layer, and a method for producing the same.

[0041] Therefore, the inventors of the present invention have conducted extensive research into the above-mentioned problems and have investigated a substrate in which an epitaxial layer heavily doped with carbon is formed on a silicon substrate instead of the buffer layer used in the prior art. All layers of this substrate can be formed sequentially in an epitaxial process, and this method is cost-effective as it does not require bonding and peeling processes.

[0042] As a result of furthering the above-mentioned investigation, the present inventors have discovered that a carbon-doped silicon epitaxial layer on a silicon substrate and a Si epitaxial layer on the silicon epitaxial layer x Ge 1-x The inventors have found that a Ge-containing substrate characterized by having a layer (0≦x<1) can be efficiently produced as a high-quality Ge-containing substrate having an intermediate layer of carbon-doped silicon formed by epitaxial growth, and have completed the present invention.

[0043] As a result of furthering the above-mentioned investigation, the present inventors have also discovered that a carbon-doped silicon layer is epitaxially grown on a silicon substrate, and a Si x Ge 1-x The present inventors have found that a high-quality Ge-containing substrate can be efficiently manufactured by forming a carbon-doped silicon layer as an intermediate layer by epitaxial growth using a method for manufacturing a Ge-containing substrate, which is characterized by growing a layer (0≦x<1), and have completed the present invention.

[0044] [Ge-containing substrate] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A schematic diagram of an example of a Ge-containing substrate according to the present invention is shown in Fig. 1. As shown in Fig. 1, the Ge-containing substrate 1 according to the present invention comprises a silicon epitaxial layer 3 doped with carbon (carbon-doped silicon layer) on a silicon single crystal substrate 2, and a Si epitaxial layer 3 on the silicon epitaxial layer 3. x Ge 1-x and a layer (Ge-containing layer) 4 (0≦x<1).

[0045] Since the carbon-doped silicon layer 3, which is an intermediate layer, is an epitaxial layer, in other words, the Ge-containing substrate is efficiently formed without performing bonding and peeling. Further, a high-quality Ge-containing substrate with reduced occurrence of defects in the peeling and bonding processes is obtained.

[0046] The carbon-doped silicon layer 3 preferably has a carbon concentration of 1×10 20 ~4×10 21 atoms / cm 3 and more preferably 4×10 20 ~8×10 20 atoms / cm 3 .

[0047] Thereby, the carbon-doped silicon layer 3 becomes better with fewer defects, and the Ge-containing layer 4 becomes of higher quality.

[0048] Note that the thickness of the carbon-doped silicon layer 3 is not particularly limited and is determined in consideration of the concentration and thickness of the Ge-containing layer 4 and the like. Preferably, it is 300 to 1000 nm.

[0049] At this time, the Si x Ge 1-x layer can be a SiGe layer (that is, 0 < x < 1). Preferably, x is 0.1 to 0.35. Thereby, the Ge-containing substrate can have a SiGe layer.

[0050] At this time, the Si x Ge 1-x layer can be a Ge layer (that is, x = 0). Thereby, the Ge-containing substrate can have a Ge layer.

[0051] [Manufacturing Method of Ge-Containing Substrate] The present invention also epitaxially grows a carbon-doped silicon layer (carbon-doped silicon layer 3) on a silicon single crystal substrate 2, and Si x Ge1-x A method for producing a Ge-containing substrate (1) is provided, characterized in that a layer (4) (0≦x<1) is grown.

[0052] The carbon-doped silicon layer 3 can be grown under the following conditions, for example. Equipment: Low-pressure CVD equipment Pressure: 1333 Pa (10 Torr) Raw material: Trimethylsilane For example, a carbon-doped Si layer is epitaxially grown on a silicon single crystal substrate 2 under reduced pressure in a low-pressure CVD apparatus using a gas obtained by mixing trimethylsilane, monomethylsilane, or monosilane gas with a carbon source.

[0053] In the method for producing a Ge-containing substrate according to the present invention, by forming the carbon-doped silicon layer 3 as the intermediate layer by epitaxial growth, all layers can be formed sequentially in the epitaxial process. In other words, the Ge-containing substrate can be produced efficiently without performing bonding and peeling. Furthermore, it is possible to produce a high-quality Ge-containing substrate in which the occurrence of defects in the peeling and bonding processes is suppressed. This can improve productivity.

[0054] At this time, the carbon concentration of the carbon-doped silicon layer 3 is set to 1×10 20 ~4×10 21 atoms / cm 3 It is preferable to set the value to 4×10 20 ~8×10 20 atoms / cm 3 It is preferable to epitaxially grow the carbon-doped silicon layer 3 at a growth temperature (substrate temperature) of 700°C to 900°C, and more preferably at 730°C to 750°C.

[0055] By performing epitaxial growth within the ranges of carbon concentration and growth temperature as described above, the carbon-doped silicon layer 3 can be formed with fewer defects and in better quality, and it can be made into a layer suitable for the growth of the Ge-containing layer 4 that follows. The ranges of these film formation temperatures and carbon concentrations can be adjusted in consideration of the concentration, thickness, etc. of the Ge-containing layer 4. For example, the film formation temperature can be 740 °C and the carbon concentration can be 5×10 20 atoms / cm 3 and so on.

[0056] Note that there is no particular limitation on the thickness of the carbon-doped silicon layer 3, and it can be adjusted in consideration of the concentration, thickness, etc. of the Ge-containing layer 4. Preferably, it is 300 to 1000 nm.

[0057] At this time, the Si x Ge 1-x layer can be made into a SiGe layer (that is, 0 < x < 1). Preferably, x is 0.1 to 0.35. Thereby, a Ge-containing substrate having a SiGe layer can be obtained.

[0058] At this time, the Si x Ge 1-x layer can be made into a Ge layer (that is, x = 0). Thereby, a Ge-containing substrate having a Ge layer can be obtained.

Example

[0059] Hereinafter, the present invention will be specifically described with reference to examples, but this does not limit the present invention.

[0060] (Example 1) A silicon single crystal substrate with a surface crystal plane orientation of (110), a diameter of 300 mm, boron doping, and a resistivity of 10 Ω·cm was prepared and placed in a reduced-pressure CVD apparatus.

[0061] Using trimethylsilane as a source gas, carbon was introduced at 1×10 20atoms / cm 3 A doped Si layer was grown to a thickness of 500 nm. Subsequently, a SiGe layer (Ge concentration = 30 atomic %) was grown using SiH2Cl2 gas and GeH4 gas as source materials at 1000 sccm each, 1333 Pa (10 Torr), and a growth temperature (substrate temperature) of 610°C for 60 minutes, producing a SiGe substrate. The SiGe substrate was suitable for use in semiconductor devices.

[0062] Example 2 On a silicon single crystal substrate of the same specifications as in Example 1, trimethylsilane was used as a source gas, and carbon was added at 4 × 10 at a growth temperature (substrate temperature) of 900 °C and 1333 Pa (10 Torr). 21 atoms / cm 3 A doped Si layer was grown to a thickness of 500 nm. Subsequently, a SiGe layer (Ge concentration = 30 atomic %) was grown using SiH2Cl2 gas and GeH4 gas as source materials at 1000 sccm each, 1333 Pa (10 Torr), and a growth temperature (substrate temperature) of 610°C for 60 minutes, producing a SiGe substrate. The SiGe substrate was suitable for use in semiconductor devices.

[0063] Example 3 On a silicon single crystal substrate of the same specifications as in Example 1, trimethylsilane was used as a source gas, and carbon was added at 1×10 at a growth temperature (substrate temperature) of 700°C and 1333 Pa (10 Torr). 20 atoms / cm 3 A doped Si layer was grown to a thickness of 500 nm. Subsequently, a Ge layer was grown using GeH gas at 1000 sccm, 1333 Pa (10 Torr), and a growth temperature (substrate temperature) of 610°C for 60 minutes to produce a Ge substrate. The Ge substrate was suitable for use in semiconductor devices.

[0064] Example 4 On a silicon single crystal substrate of the same specifications as in Example 1, trimethylsilane was used as a source gas, and carbon was added at 4 × 10 at a growth temperature (substrate temperature) of 900 °C and 1333 Pa (10 Torr). 21 atoms / cm 3A doped Si layer was grown to a thickness of 500 nm. Subsequently, a Ge layer was grown using GeH gas at 1000 sccm, 1333 Pa (10 Torr), and a growth temperature (substrate temperature) of 610°C for 60 minutes to produce a Ge substrate. The Ge substrate was suitable for use in semiconductor devices.

[0065] As described above, according to the examples of the present invention, a Ge-containing substrate suitable as a semiconductor substrate can be fabricated by epitaxially growing a carbon-doped silicon layer on a silicon substrate without performing a peeling and bonding process.

[0066] The present specification includes the following aspects. [1]: A carbon-doped silicon epitaxial layer on a silicon substrate, and a Si layer on the silicon epitaxial layer. x Ge 1-x layer (0≦x<1). [2]: The carbon concentration of the silicon epitaxial layer is 1×10 20 ~4×10 21 atoms / cm 3 The Ge-containing substrate according to [1] above, [3]: The carbon concentration of the silicon epitaxial layer is 4 × 10 20 ~8×10 20 atoms / cm 3 The Ge-containing substrate according to [1] or [2] above, [4]: The above-mentioned Si x Ge 1-x The Ge-containing substrate of [1], [2] or [3] above, wherein the layer is a SiGe layer. [5]: The above-mentioned Si x Ge 1-x The Ge-containing substrate of [1], [2], [3] or [4] above, wherein the layer is a Ge layer. [6]: A carbon-doped silicon layer is epitaxially grown on a silicon substrate, and a Si x Ge 1-xA method for producing a Ge-containing substrate comprising growing a layer (0≦x<1). [7]: The carbon concentration of the carbon-doped silicon layer is 1 × 10 20 ~4×10 21 atoms / cm 3 The method for producing a Ge-containing substrate according to [6] above, comprising: [8]: The carbon concentration of the carbon-doped silicon layer is 4 × 10 20 ~8×10 20 atoms / cm 3 The method for producing a Ge-containing substrate according to [6] or [7] above, comprising: [9]: The method for producing a Ge-containing substrate according to [6], [7] or [8], comprising epitaxially growing the carbon-doped silicon layer at 700 to 900°C.

[10] : The method for producing a Ge-containing substrate according to [6], [7], [8] or [9], comprising epitaxially growing the carbon-doped silicon layer at 730 to 750°C.

[11] : The Si x Ge 1-x The method for producing a Ge-containing substrate according to [6], [7], [8], [9] or

[10] above, comprising forming the layer as a SiGe layer.

[12] : The above-mentioned Si x Ge 1-x The method for producing a Ge-containing substrate according to [6], [7], [8], [9],

[10] or

[11] above, comprising forming the layer as a Ge layer.

[0067] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0068] 1...Ge-containing substrate, 2...silicon single crystal substrate, 3...Silicon epitaxial layer (carbon-doped silicon layer), 4…Si x Ge 1-x Layer (Ge contains layers).

Claims

1. A carbon-doped silicon epitaxial layer on a silicon substrate, and a Si layer on the silicon epitaxial layer. ｘ Ge １－ｘ and a layer (0≦x<1).

2. The carbon concentration of the silicon epitaxial layer is 1×10 ２０ ~4 x 10 ２１ atoms / cm ３ 2. The Ge-containing substrate according to claim 1, wherein:

3. The carbon concentration of the silicon epitaxial layer is 4×10 ２０ ~8 x 10 ２０ atoms / cm ３ 2. The Ge-containing substrate according to claim 1, wherein:

4. The Si ｘ Ge １－ｘ 4. The Ge-containing substrate according to claim 1, wherein the layer is a SiGe layer.

5. The Si ｘ Ge １－ｘ 4. The Ge-containing substrate according to claim 1, wherein the layer is a Ge layer.

6. A carbon-doped silicon layer is epitaxially grown on a silicon substrate, and a Si layer is formed on the carbon-doped silicon layer. ｘ Ge １－ｘ 1. A method for producing a Ge-containing substrate, comprising growing a layer (0≦x<1).

7. The carbon concentration of the carbon-doped silicon layer is set to 1×10 ２０ ~4 x 10 ２１ atoms / cm ３ 7. The method for producing a Ge-containing substrate according to claim 6, wherein:

8. The carbon concentration of the carbon-doped silicon layer is set to 4×10 ２０ ~8 x 10 ２０ atoms / cm ３ 7. The method for producing a Ge-containing substrate according to claim 6, wherein:

9. 7. The method for producing a Ge-containing substrate according to claim 6, wherein the carbon-doped silicon layer is epitaxially grown at a temperature of 700 to 900.degree.

10. 7. The method for producing a Ge-containing substrate according to claim 6, wherein the carbon-doped silicon layer is epitaxially grown at a temperature of 730 to 750.degree.

11. The Si ｘ Ge １－ｘ 11. The method for producing a Ge-containing substrate according to claim 6, wherein the layer is a SiGe layer.

12. The Si ｘ Ge １－ｘ 11. The method for producing a Ge-containing substrate according to claim 6, wherein the layer is a Ge layer.

Images