Ge-CONTAINING SUBSTRATE, AND METHOD FOR MANUFACTURING Ge-CONTAINING SUBSTRATE

Abstract

The present invention is a Ge-containing substrate characterized by having: a silicon epitaxial layer doped with carbon on a silicon substrate; and a SixGe1-x layer (0≤x<1) on the silicon epitaxial layer. Thus provided is a high-quality, efficiently manufactured Ge-containing substrate having an Si substrate and a Ge-containing layer.

Description

Ge-containing substrate and method for manufacturing the Ge-containing substrate

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

[0002] SiGe and Ge are materials widely used in various devices such as electronic, optical, and RF devices. In particular, SiGe has recently been proposed as a replacement for the Fin structure currently used in logic ICs, and for next-generation semiconductors, GAA (Gate All Around) and CFET (Complementary Field Effect Transistor) stacking NMOS and CMOS have been proposed, and SiGe is a material that plays an important role in the manufacturing process of these devices (Non-Patent Document 1).

[0003] JP 2007-180285 A JP 2004-363592 A

[0004] The 1st Workshop of the Industry-Academia Collaboration Committee on Crystal Growth, Processing, and Evaluation of Semiconductors, Japan Society of Applied Physics, "Crystal Technology Supporting the Revival of Semiconductors," Yonenaga, "Growth of High-Quality SiGe Crystals and Elucidation of Their Fundamental Properties," Materia, 47(1), 3 (2008); Sato, "Fundamentals and Challenges of Heteroepitaxy: 1st Workshop of the 3C-SiC Technology Study Group for IoT in Harsh Environments" (2019); Wong, L. H. "Strain Relaxation in SiGe / Si Heteroepitaxy." Doctoral Thesis, Nanyang Technological University, Singapore, (2007). E. A. Fitgerald, et. al. , “Totally relaxed GexSi1-x layers with low threading dislocation densities grows on Si substrares”, App. Phys. Lett. , 59, 811 (1991). F. K. Le Geues, et. al. , “Mechanism and conditions for anomalous strain relaxation in graded thin films and superlattices”, App. Phys. Lett. , 71, 4230 (1992). T. Taniguchi, et. al. , Abst. of SAP Spring Meeting. , 17a-F102-9 (2018). T. Taniguchi, et. al. , Abst. of JSAP Autumn Meeting. , 20p-234-10 (2018).

[0005] However, in the equilibrium phase diagram, the liquidus and solidus of SiGe are widely separated, and the distribution coefficient is 2 to 5, which is greater than 1, making it known that SiGe 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), how to mitigate the difference in lattice constants between Si and Ge is crucial. 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, assuming x is 0.3, the lattice constant is 0.5493 ​​nm, resulting in a minimal lattice mismatch of 0.14%. This lattice mismatch can lead to dislocations and defects 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 a 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 sufficiently lattice-relaxed, high-quality 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; then, 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 enables the formation of the barrier layer and the interdiffusion of Ge, thereby forming a sufficiently lattice-relaxed single-crystal SiGe layer on the barrier layer.

[0010] As described above, various methods have been investigated. However, the methods described in Patent Documents 1 and 2 in particular are premised on the bonding and peeling processes, and the occurrence of defects in these processes is unavoidable, and an increase in the number of substrate manufacturing processes is unavoidable.

[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.

[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 silicon epitaxial layer on the silicon epitaxial layer. ｘ Ge １－ｘ and a layer (0≦x<1) of Ge-containing substrate.

[0014] Such a Ge-containing substrate has an intermediate layer of 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 x 10 ２１ atoms / cm ３It 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 x 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 The present invention provides a method for producing a Ge-containing substrate, 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 x 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 x 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 a temperature of 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 makes it possible to obtain a Ge-containing substrate having a Ge layer.

[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, the method for producing a Ge-containing substrate of the present invention makes it possible to efficiently produce a high-quality Ge-containing substrate by forming an intermediate layer of a carbon-doped silicon layer by epitaxial growth.

[0038] 1 shows a schematic diagram of an example of a Ge-containing substrate according to the present 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 an efficiently produced Ge-containing substrate having 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] 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 layer is deposited on the carbon-doped silicon layer. ｘ Ge １－ｘThe inventors have found that a high-quality Ge-containing substrate can be efficiently manufactured by forming a carbon-doped silicon layer by epitaxial growth as an intermediate layer using a method for manufacturing a Ge-containing substrate, characterized by growing a layer (0≦x<1), and have completed the present invention.

[0044] [Ge-containing substrate] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows a schematic diagram of an example of a Ge-containing substrate according to the present invention. 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] The Ge-containing substrate 1 is an epitaxial layer having the carbon-doped silicon layer 3 as the intermediate layer, which means that the Ge-containing substrate 1 is efficiently formed without bonding or peeling. Furthermore, the Ge-containing substrate 1 is a high-quality Ge-containing substrate in which the occurrence of defects in the peeling and bonding steps is suppressed.

[0046] The carbon-doped silicon layer 3 has a carbon concentration of 1×10 ２０ ~4 x 10 ２１ atoms / cm ３ Preferably, it is 4×10 ２０ ~8 x 10 ２０ atoms / cm ３ It is more preferable that:

[0047] This results in a better carbon-doped silicon layer 3 with fewer defects, and a higher quality Ge-containing layer 4.

[0048] There is no particular limitation on the thickness of the carbon-doped silicon layer 3, and it is determined in consideration of the concentration and thickness of the Ge-containing layer 4. The thickness is preferably 300 to 1000 nm.

[0049] At this time, Si ｘ Ge １－ｘThe layer may be a SiGe layer (i.e., 0<x<1), where x is preferably 0.1 to 0.35, so that the Ge-containing substrate has a SiGe layer.

[0050] At this time, Si ｘ Ge １－ｘ The layer may be a Ge layer (i.e., x=0), thereby allowing the Ge-containing substrate to have a Ge layer.

[0051] [Method for manufacturing a Ge-containing substrate] The present invention also relates to a method for manufacturing a Ge-containing substrate, which comprises epitaxially growing a carbon-doped silicon layer (carbon-doped silicon layer 3) on a silicon single crystal substrate 2, and then growing a Si ｘ Ge １－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: Apparatus: low-pressure CVD apparatus Pressure: 1333 Pa (10 Torr) Source material: trimethylsilane For example, a carbon-doped Si layer is epitaxially grown on the 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 x 10 ２１ atoms / cm ３ It is preferable to set the value to 4×10 ２０ ~8 x 10 ２０atoms / 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 above carbon concentration and growth temperature ranges, the carbon-doped silicon layer 3 can be formed with fewer defects and in a good condition, making it suitable for the subsequent growth of the Ge-containing layer 4. The ranges of the film formation temperature and carbon concentration can be adjusted in consideration of the concentration, thickness, etc. of the Ge-containing layer 4. For example, when the film formation temperature is 740°C and the carbon concentration is 5×10 ２０ atoms / cm ３ It can be said that:

[0056] There is no particular limitation on the thickness of the carbon-doped silicon layer 3, and it can be adjusted in accordance with the concentration, thickness, etc. of the Ge-containing layer 4. The thickness is preferably 300 to 1000 nm.

[0057] At this time, Si ｘ Ge １－ｘ The layer can be a SiGe layer (i.e., 0<x<1), where x is preferably 0.1 to 0.35. This makes it possible to obtain a Ge-containing substrate having a SiGe layer.

[0058] At this time, Si ｘ Ge １－ｘ The layer can be a Ge layer (i.e., x=0), which results in a Ge-containing substrate having a Ge layer.

[0059] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

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

[0061] On the silicon single crystal substrate, carbon was added at 1×10 at a growth temperature (substrate temperature) of 700° C. and 1333 Pa (10 Torr) using trimethylsilane as a source gas. ２０ atoms / cm ３ A doped Si layer was grown to 500 nm. ２ Cl ２ Gas and GeH ４ A SiGe layer (Ge concentration = 30 atomic %) was grown at a growth temperature (substrate temperature) of 610°C for 60 minutes at 1000 sccm and 1333 Pa (10 Torr) using the gases as source materials, to produce a SiGe substrate. The SiGe substrate was suitable for use as a semiconductor device.

[0062] Example 2 A silicon single crystal substrate having the same specifications as Example 1 was grown using trimethylsilane as a source gas at a growth temperature (substrate temperature) of 900° C. and 1333 Pa (10 Torr) with 4×10 carbon atoms. ２１ atoms / cm ３ A doped Si layer was grown to 500 nm. ２ Cl ２ Gas and GeH ４ A SiGe layer (Ge concentration = 30 atomic %) was grown at a growth temperature (substrate temperature) of 610°C for 60 minutes at 1000 sccm and 1333 Pa (10 Torr) using the gases as source materials, to produce a SiGe substrate. The SiGe substrate was suitable for use as a semiconductor device.

[0063] Example 3 A silicon single crystal substrate having the same specifications as Example 1 was grown using trimethylsilane as a source gas at a growth temperature (substrate temperature) of 700° C. and 1333 Pa (10 Torr) with 1×10 carbon. ２０ atoms / cm ３ A doped Si layer was grown to a thickness of 500 nm. ４ A Ge layer was grown using the gas as a source material 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 as a semiconductor device.

[0064] Example 4 A silicon single crystal substrate having the same specifications as Example 1 was grown using trimethylsilane as a source gas at a growth temperature (substrate temperature) of 900° C. and 1333 Pa (10 Torr) with 4×10 carbon atoms. ２１ atoms / cm ３ A doped Si layer was grown to a thickness of 500 nm. ４ A Ge layer was grown using the gas as a source material 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 as a semiconductor device.

[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] This specification includes the following aspects: [1]: A carbon-doped silicon epitaxial layer on a silicon substrate, and a Si on the silicon epitaxial layer. ｘ Ge １－ｘ [2]: the carbon concentration of the silicon epitaxial layer is 1×10 ２０ ~4 x 10 ２１ atoms / cm ３ [3]: the carbon concentration of the silicon epitaxial layer is 4×10 ２０ ~8 x 10 ２０ atoms / cm ３ The Ge-containing substrate according to the above [1] or [2], wherein the Si ｘ Ge １－ｘ The Ge-containing substrate according to the above [1], [2] or [3], wherein the layer is a SiGe layer. ｘ Ge １－ｘ [6]: A method for forming a silicon layer doped with carbon on a silicon substrate by epitaxial growth, and forming a silicon layer on the silicon layer doped with carbon. ｘ Ge１－ｘ [7]: a carbon concentration of the carbon-doped silicon layer is 1×10 ２０ ~4 x 10 ２１ atoms / cm ３ [8]: The method for manufacturing a Ge-containing substrate according to the above [6], comprising: ２０ ~8 x 10 ２０ atoms / cm ３ [9]: A method for producing a Ge-containing substrate according to [6] or [7] above, comprising epitaxially growing the carbon-doped silicon layer at 700 to 900°C.

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

[11] : A method for producing a Ge-containing substrate according to [6], [7], [8] or [9] above, comprising epitaxially growing the carbon-doped silicon layer at 730 to 750°C. ｘ Ge １－ｘ

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

[10] , comprising forming the SiGe layer. 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 Ge layer.

[0067] The present invention is not limited to the above-described embodiments. The above-described embodiments 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 exhibits similar effects is included within the technical scope of the present invention.

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

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

6. Epitaxially growing a carbon-doped silicon layer on a silicon substrate, and forming a Si layer 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 increased 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 increased 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. 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°C.

10. 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°C.

11. The above-mentioned 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 above-mentioned 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.

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