A method for epitaxial growth of antimony doped silicon on a silicon substrate

Abstract

The application discloses a method for Sb-doped epitaxy on silicon substrate, and belongs to the technical field of semiconductor manufacturing. The method is performed in an epitaxial CVD reaction furnace, in which a silicon source gas and a Sb-doped mixed gas containing SbH3 and SbCl3 are introduced into a reaction chamber to perform epitaxial growth on the surface of a silicon substrate. The SbH3 and SbCl3 are used in the method to achieve a synergistic effect in the epitaxial process: SbCl3 can inhibit the gas phase pre-decomposition of SbH3, and improve the doping uniformity; meanwhile, the hydrogen generated by the decomposition of SbH3 can neutralize the chlorine radicals generated by SbCl3, and reduce the etching of the silicon surface, so that a Sb-doped epitaxial layer with high uniformity, low defect density and excellent surface quality can be obtained within a wide process window. The method can be applied to conventional CVD epitaxial equipment, and even to large-size epitaxy such as 12-inch epitaxy, and is easy to integrate into the existing production line.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method for antimony-doped epitaxy on a silicon substrate. Background Technology

[0002] In the manufacture of advanced logic and memory devices, antimony-doped silicon epitaxial layers are crucial for forming specific electrical properties. Silicon epitaxial layers are typically grown using CVD (chemical vapor deposition) methods. For example, ASM's 300mm or 200mm epitaxial furnaces are CVD silicon epitaxial growth equipment, industry-leading single-wafer processing systems with precise temperature, pressure, and gas flow control capabilities, and are widely used in silicon epitaxial processes. However, achieving high uniformity and low-defect antimony (Sb)-doped epitaxy on such advanced equipment has always been a challenge. One significant reason for the difficulty in antimony-doped epitaxy is the different technical problems encountered by various Sb doping sources during the epitaxial process.

[0003] For example, SbH3 (antimonane) is one of the main antimony doping sources for silicon epitaxial growth. However, due to its high chemical reactivity, when SbH3 is used as the antimony doping source for antimony-doped silicon epitaxy, it is prone to pre-decomposition after entering the CVD reaction chamber, especially upstream of the gas flow path and in the high-temperature region. This results in the partial consumption of antimony atoms before they reach the wafer surface, causing poor uniformity of doping concentration within and between wafers, and potentially leading to particulate contamination due to gas-phase nucleation, affecting device yield. Especially for high-temperature ranges, such as thick epitaxy with epitaxial temperatures above 1000℃, SbH3 is extremely reactive, and its rapid decomposition not only leads to defects and extremely non-uniform resistivity, but may even prevent the completion of the doped epitaxial process.

[0004] SbCl3 is also one of the main antimony doping sources for epitaxial growth. When SbCl3 is used as the antimony doping source for antimony-doped silicon epitaxy, chlorine free radicals are released during the decomposition process. These chlorine free radicals will corrode the silicon surface, especially at low temperature process windows (such as below 750°C), which will have a significant etching effect on the silicon substrate surface, resulting in increased surface roughness, increased defect density, and difficulty in obtaining high-quality epitaxial layers with atomically flat surfaces.

[0005] The aforementioned factors pose significant challenges to current Sb-doped epitaxial processes in terms of doping uniformity, surface quality, and defect control, making it difficult to obtain high-quality epitaxial layers. Therefore, there is an urgent need for an epitaxial method that can overcome the various defects encountered by the aforementioned gas sources, enabling the realization of antimony-doped silicon epitaxial processes with excellent uniformity, superior surface quality, and a wide process window on widely used CVD epitaxial equipment such as ASM epitaxial furnaces. Summary of the Invention

[0006] This invention aims to address the technical problems encountered in the prior art when using a single antimony doping source (SbH3 or SbCl3) for antimony-doped silicon epitaxy in a CVD epitaxial reactor. Specifically, SbH3's high reactivity leads to pre-decomposition, resulting in poor doping uniformity and particle contamination; and SbCl3's low-temperature etching by chlorine radicals causes high defect density and poor surface quality on the silicon surface. The invention provides a method for antimony-doped epitaxy on a silicon substrate. This method effectively suppresses the pre-decomposition of SbH3 while reducing the etching effect of SbCl3 on the silicon surface, thereby obtaining an antimony-doped silicon epitaxial layer with high uniformity, low defect density, and excellent surface quality under a wide process window.

[0007] The present invention achieves the above-mentioned objectives through the following technical solutions.

[0008] This invention first provides a method for antimony-doped epitaxy on a silicon substrate. The method is carried out in a CVD epitaxy furnace, using a mixed gas of SbH3 and SbCl3 as the antimony doping source. By precisely controlling the pressure, temperature and gas mixing ratio, the synergistic effect of the two gas doping sources is stimulated under different application scenarios.

[0009] Furthermore, the method includes the following steps:

[0010] Step 1) Silicon substrate preparation and loading: Provide a clean silicon substrate and load it into the reaction chamber of the epitaxial furnace. For example: Provide a 300mm single-crystal silicon substrate with a surface cleaned by standard RCA, and transfer it into the reaction chamber through the load lock of the epitaxial growth equipment.

[0011] Step 2) Reaction Chamber Pretreatment and Substrate Preheating: The reaction chamber is evacuated to a high vacuum, and the substrate is baked at high temperature in an H2 atmosphere to obtain a clean silicon surface. For example, the reaction chamber is evacuated to a pressure <1.0 × 10⁻⁶. -5 Torr; Under an H2 atmosphere, the substrate temperature is raised to a high-temperature baking temperature of 800℃~1100℃ and held for 10~60 seconds to remove the natural oxide layer on the silicon substrate surface and obtain a clean atomic-level silicon surface.

[0012] Step 3) Epitaxial Growth and Doping: The reaction chamber pressure and substrate temperature are set. A mixed gas containing silicon source gas and the aforementioned SbH3 and SbCl3 is introduced into the reaction chamber to perform antimony-doped epitaxial growth on the silicon substrate surface. Specifically, this includes:

[0013] a) Set the reaction chamber pressure: Based on the characteristics of the target epitaxial layer, set the pressure in the range of 5 Torr to 100 Torr.

[0014] More preferably, for selective epitaxy of the target epitaxial layer: which requires high step coverage, a low-pressure range is used, i.e., the reaction chamber pressure is set in the range of 5-50 Torr. Under this pressure, the gas phase reaction is suppressed and the surface reaction dominates. At this time, the Cl component in the mixed gas can effectively suppress the parasitic deposition of polycrystalline silicon on the dielectric layer. For external epitaxial growth of the target epitaxial layer: a medium-pressure range is used, i.e., the reaction chamber pressure is set in the range of 50-100 Torr. Under this pressure range, a balance can be achieved between growth rate and uniformity.

[0015] b) Setting the substrate temperature: The substrate temperature is controlled between 600°C and 1100°C, and different synergistic mechanisms of the SbH3 and SbCl3 mixed gas are used for different temperature ranges.

[0016] In the low-temperature range (600-750℃), the spontaneous decomposition of SbH3 is suppressed, while the etching effect of SbCl3 is more significant. By using a mixed gas, the H• generated by the decomposition of SbH3 can be effectively neutralized by the Cl• generated by SbCl3, thereby suppressing the etching of the silicon surface by Cl•. This makes it possible to obtain high-quality epitaxial layers in ultra-shallow junctions or low-temperature applications with strict thermal budget requirements.

[0017] In the mid-temperature range (750-900℃), the decomposition and neutralization reactions of SbH3 and SbCl3 reach optimal equilibrium, making it the preferred window for achieving excellent crystal quality and precise control of antimony doping.

[0018] In the high-temperature range (900-1100℃), SbH3 is very reactive. The "dilution" effect of SbCl3 is used to stabilize the highly reactive SbH3 and prevent it from decomposing too quickly and causing defects. At the same time, excess Cl can be effectively removed by hydrogen in the H2 carrier gas, which can achieve a balance between growth rate and antimony doping uniformity.

[0019] c) Introducing the reaction gas: Using H2 as the carrier gas, a silicon source gas and a SbH3 / SbCl3 mixed gas are introduced. The total gas flow rate is automatically controlled by the equipment to maintain the set pressure. The molar mixing ratio of SbH3 to SbCl3 is controlled between 1:10 and 10:1, preferably between 1:3 and 3:1, to achieve optimal neutralization effect and doping efficiency. The total antimony doping source flow rate is 1~500 sccm, with the specific flow rate depending on the target doping concentration (e.g., 1e15~1e19 atoms / cm). 3The process formulation is set accordingly. The silicon source gas is either dichlorosilane (DCS) or trichlorosilane (TCS). Using a chlorinated silicon source allows it to work synergistically with the Cl component in the antimony-doped source. The silicon source gas flow rate is controlled within the range of 100~1000 sccm. H2 serves not only as a carrier gas but also as a reducing agent for SbCl3 and a scavenger for excess Cl.

[0020] Step 4) Growth Termination and Cooling: After reaching the target epitaxial layer thickness, stop the introduction of silicon source and antimony doping source gas, cool down, and remove the epitaxial wafer.

[0021] The key to this invention lies in the creative use of SbH3 and SbCl3 in combination and the revelation of their synergistic mechanism.

[0022] Firstly, it achieves the effect of suppressing pre-decomposition and improving doping uniformity: In the mixed gas, the relatively stable and less prone to pre-decomposition SbCl3 acts as a "diluter" and "slow-releaser" of the highly active SbH3. This physical mixing reduces the local concentration of SbH3 in the gas phase, effectively delaying its premature decomposition in the upstream region of the reaction chamber. This allows more antimony dopant sources to be safely transported to the wafer surface for decomposition and incorporation, thereby significantly improving the uniformity of doping within and between wafers. This effect is particularly prominent in large-scale CVD epitaxial systems with specific airflow designs, such as ASM epitaxial furnaces.

[0023] Furthermore, the neutralization etching effect and improved surface quality: Chlorine free radicals generated by the decomposition of SbCl3 are the main culprits of surface etching. However, in the mixed gas system of this invention, hydrogen free radicals generated by the decomposition of SbH3 can react with chlorine free radicals generated by SbCl3 to generate stable HCl, which is carried away by the H2 carrier gas. This "in-situ neutralization" effect, especially in the low-temperature process window (600℃-750℃), greatly suppresses the etching of silicon surfaces by chlorine, making it possible to achieve antimony-doped epitaxial growth with low defect density and atomically flat surface quality under low-temperature conditions where good surface quality cannot be obtained by traditional single SbCl3 source processes.

[0024] Extended Process Window: By adjusting the molar mixing ratio of SbH3 to SbCl3 (preferably 1:10 to 10:1, more preferably 1:3 to 3:1), the doping behavior can be "fine-tuned" according to the reaction temperature and epitaxial thickness. This allows for the coordination of different antimony doping sources or different substrates for epitaxy (such as selective epitaxy and in vitro epitaxy) under different reaction temperatures, reaction chamber pressures, and other conditions, enabling high-quality epitaxy to be achieved across a relatively wide process window. For example, when thick epitaxy is required in a high-temperature range, the proportion of SbCl3 can be appropriately increased to stabilize the process due to the high activity of SbH3 in the high-temperature region. In a low-temperature range where etching needs to be avoided, the proportion of SbH3 can be appropriately increased to provide sufficient neutralization capacity. This flexible control capability allows the same reaction chamber to adapt to a wide range of applications, from ultra-shallow junctions to thick epitaxy. Furthermore, by adjusting the gas mixing ratio, a wide range of precise control from light to heavy doping can be achieved in the same reaction chamber, enabling gradient doping.

[0025] Compared with the prior art, the present invention has the following significant advantages and positive effects:

[0026] Excellent process uniformity: It solves the problem of SbH3 pre-decomposition and, combined with the precision control of CVD epitaxy equipment commonly used in the industry such as ASM epitaxial furnace, can achieve nanometer-level thickness uniformity of <5% and resistivity uniformity of <10% within the wafer.

[0027] Excellent surface quality: This invention utilizes the synergistic effect of two antimony doping sources, SbH3 and SbCl3. Especially in the low-temperature range (such as 700℃), through the neutralization of chlorine free radicals, an atomically smooth surface can be obtained with an RMS roughness of less than 1 nm.

[0028] High equipment compatibility: This method can be directly integrated into existing ASM epitaxial furnaces, requiring only the configuration of a corrosion-resistant SbCl3 gas path. No major modifications to the core hardware of the equipment are needed, and it can be implemented directly on existing production lines.

[0029] Through the above-described collaborative design, the present invention can achieve excellent process uniformity, an extended process window, superior surface quality, and high integration with existing epitaxial equipment. Attached Figure Description

[0030] Figure 1 This is an atomic force (AFM) microscope image of the epitaxial wafer surface obtained in Example 1 of the present invention.

[0031] Figure 2 This is an image of the epitaxial wafer obtained in Example 2 of the present invention after etching.

[0032] Figure 3This is a microscopic image of stacking fault defects on the epitaxial wafer obtained in Example 2 of the present invention after etching.

[0033] Figure 4 This is a resistivity test diagram of the epitaxial wafer prepared in Embodiment 2 of the present invention.

[0034] Figure 5 This is an atomic force (AFM) microscope image of the epitaxial wafer surface obtained in Example 3 of the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0036] Example 1

[0037] This embodiment performs low-temperature selective epitaxy of ultra-shallow junctions using a conventional ASM epitaxy system, specifically an ASM EPI3200 300mm epitaxy furnace. The specific steps are as follows:

[0038] Step 1), Substrate preparation and loading: A 300mm single-crystal silicon substrate with a patterned SiO2 mask on its surface is used. The substrate is cleaned with standard RCA and transferred to the epitaxial furnace reaction chamber through the transfer cavity.

[0039] Step 2), Substrate pretreatment: Evacuate the reaction chamber to a base pressure <1.0×10⁻⁶. -5 Torr. In a pure H2 atmosphere, the substrate was baked at 850°C for 30 seconds to remove the natural oxide layer on the surface.

[0040] Step 3), Epitaxial Growth: Set the reaction chamber pressure to 5 Torr, this low pressure facilitates selective growth; set the substrate temperature to 700℃ (low-temperature window); introduce silicon source gas: SiH2Cl2; flow rate 150 sccm; simultaneously introduce antimony doping sources SbH3 and SbCl3, which are mixed near the reaction chamber inlet or directly in the reaction chamber nozzle, with a mixing molar ratio of 3:1, and a total antimony doping gas flow rate of 10 sccm. The carrier gas is high-purity H2, and the total gas flow rate is automatically controlled by the equipment according to the reaction chamber pressure.

[0041] Step 4), Growth Termination: After epitaxial growth for 60 seconds under the conditions of Step 3), stop the reaction gas silicon source and antimony doping source, then cool down to below 600℃ and remove the epitaxial wafer to obtain a uniformly antimony-doped selective epitaxial wafer.

[0042] Under an optical microscope, the ultra-shallow junction low-temperature selective epitaxial wafer of this embodiment can be observed. Its epitaxial layer grows only in the single-crystal silicon region, with no polycrystalline silicon deposition on the SiO2 mask, achieving perfect selective epitaxy. The epitaxial layer thickness is approximately 15 nm, and SIMS analysis shows a steep doping profile. Analysis of the surface morphology of the epitaxial layer, such as... Figure 1 The image shows an atomic force micrograph (AFM) of the epitaxial layer obtained in this embodiment. The figure shows that the average surface roughness (Ra) of the epitaxial layer is 0.27 nm, indicating excellent surface quality and an atomically smooth surface. Clearly, this embodiment uses a mixed gas of SbH3 and SbCl3 as the doping source. By controlling appropriate gas pressure and doping ratio, under a low-temperature process window, SbCl3 releases chlorine radicals that corrode the silicon surface. These chlorine radicals are then neutralized in situ by hydrogen radicals generated from the decomposition of SbH3, inhibiting the etching of the silicon surface by chlorine. This achieves a low-temperature process for obtaining an epitaxial layer with a good surface in the presence of the SbCl3 source, realizing the growth of antimony-doped epitaxial layers with atomically smooth surface quality.

[0043] Example 2

[0044] In this embodiment, in vitro epitaxial growth is performed using an ASM EPI3200 300mm epitaxial furnace. The specific steps are as follows:

[0045] Step 1), Substrate preparation and loading: A 300mm diameter P-type silicon polished wafer is used as the substrate. The substrate is cleaned using standard RCA and then transferred to the epitaxial furnace reaction chamber via a transfer cavity.

[0046] Step 2), Substrate pretreatment: Evacuate the reaction chamber to a base pressure <1.0×10⁻⁶. -5 Torr. In a pure H2 atmosphere, the substrate was baked at 1110°C for 30 seconds to remove the natural oxide layer on the surface.

[0047] Step 3), Epitaxial Growth: Set the reaction chamber pressure to 60 Torr, which is beneficial for balancing the growth rate and uniformity; set the substrate temperature to 1000℃ (high-temperature window); introduce the silicon source gas trichlorosilane at a flow rate of 500 sccm; simultaneously introduce antimony doping sources SbH3 and SbCl3, which are mixed near the reaction chamber inlet or directly in the reaction chamber nozzle at a molar ratio of 1:3, with a total antimony atom flow rate of 100 sccm. The carrier gas is high-purity H2, and the total gas flow rate is automatically controlled by the equipment based on the reaction chamber pressure.

[0048] Step 4), Growth Termination: After epitaxial growth for 10 minutes under the conditions of Step 3), stop the reaction gas silicon source and antimony doping source, and then cool down to below 600℃ and remove.

[0049] The Sb-doped epitaxial wafer prepared in this embodiment was tested, and the results showed that: an antimony-doped epitaxial layer with a thickness of approximately 3 μm was obtained in this embodiment, the growth rate of the epitaxial process was approximately 300 nm / min, and the thickness uniformity across the entire wafer reached 3%. The crystal quality is excellent, such as... Figure 2 This is an image of the epitaxial layer after etching in this embodiment. No slip lines are visible, and the dislocation density is less than 1000 cm⁻¹. -2 Observe its corrosion defects under a microscope, such as... Figure 3 This is a stacking fault distribution diagram of a local area after the epitaxial layer etching in this embodiment, showing a relatively small defect distribution. The Sb doping uniformity is also excellent, such as... Figure 4 The resistivity test diagram of the epitaxial wafer in this embodiment shows that the average resistivity is 0.386 Ω·cm and the intra-wafer uniformity of resistivity is 3.38%, indicating that uniform Sb doping has been obtained. This overcomes the problems of poor doping concentration uniformity and particle defects caused by the decomposition of SbH3 at high temperature. In the doping source mixed gas, the relatively stable and non-decomposed SbCl3 plays the role of "diluting" and "slowly releasing" the highly active SbH3, thereby achieving the effect of suppressing pre-decomposition and improving doping uniformity.

[0050] Example 3

[0051] In this embodiment, in vitro epitaxial growth is performed using an ASM EPI3200 300mm epitaxial furnace. The specific steps are as follows:

[0052] Step 1), Substrate preparation and loading: A 300mm diameter P-type silicon polished wafer is used as the substrate. The substrate is cleaned using standard RCA and then transferred to the epitaxial furnace reaction chamber via a transfer cavity.

[0053] Step 2), Substrate pretreatment: Evacuate the reaction chamber to a base pressure <1.0×10⁻⁶. -5 Torr. In a pure H2 atmosphere, the substrate was baked at 1110°C for 30 seconds to remove the natural oxide layer on the surface.

[0054] Step 3), Epitaxial Growth: The reaction chamber pressure is set to 60 Torr to balance growth rate and uniformity; the substrate temperature is set to 800℃, within this medium-high temperature window, where the decomposition and neutralization of SbH3 and SbCl3 reach equilibrium; dichlorosilane (DCS) silicon source gas is introduced at a flow rate of 300 sccm; simultaneously, antimony doping sources SbH3 and SbCl3 are introduced, and the two are mixed near the reaction chamber inlet or directly within the reaction chamber nozzle, with a 1:1 molar ratio to achieve a balance between neutralization effect and doping efficiency; the total antimony atom flow rate is 50 sccm, corresponding to a medium doping concentration of approximately 5e17 atoms / cm. 3 The carrier gas is high-purity H2, and the total gas flow rate is automatically controlled by the equipment based on the reaction chamber pressure.

[0055] Step 4), Growth Termination: After epitaxial growth for 5 minutes under the conditions of Step 3), the target thickness is about 1.5 μm. Stop the reaction gas silicon source and antimony doping source, and then cool down to below 600℃ and remove it.

[0056] In this embodiment, the antimony-doped epitaxy achieves peak performance in the mid-temperature range under the synergistic effect of the mixed gas: the hydrogen radicals generated by the decomposition of SbH3 effectively neutralize the chlorine radicals of SbCl3, reducing surface etching; simultaneously, SbCl3 dilutes SbH3, suppressing pre-decomposition. The resulting epitaxial layer exhibits a thickness uniformity of <4% and a resistivity uniformity of <8%. The surface quality is close to atomic-level smoothness, and the roughness test results are as follows: Figure 5 The data indicates that the average roughness Ra is 0.73 nm.

[0057] Example 4

[0058] This embodiment performs low-temperature selective epitaxy, using an ASM EPI3200 300mm epitaxial furnace. The specific steps are as follows:

[0059] Step 1), Substrate preparation and loading: A 300mm diameter single-crystal silicon substrate with a patterned SiO2 mask is used. The substrate is cleaned with standard RCA and loaded into the epitaxial furnace reaction chamber.

[0060] Step 2), Substrate pretreatment: Evacuate the reaction chamber to a base pressure <1.0×10⁻⁶. -5 Torr. In a pure H2 atmosphere, the substrate was baked at 850°C for 30 seconds to remove the natural oxide layer on the surface.

[0061] Step 3), Epitaxial Growth: The reaction chamber pressure is set to 10 Torr, a low-pressure extreme that facilitates highly selective epitaxy; the substrate temperature is set to 600℃; trichlorosilane (TCS) silicon source gas is introduced at a flow rate of 100 sccm, while a mixture of antimony doping source gas SbH3 and SbCl3 is simultaneously introduced at a molar ratio of 10:1, with high SbH3 providing sufficient hydrogen radicals to neutralize chlorine; the total antimony doping gas flow rate is 5 sccm, a low flow rate for approximately 1e16 atoms / cm. 3 The light doping concentration is [not specified]. The carrier gas is high-purity H2, and the total gas flow rate is automatically controlled by the equipment based on the reaction chamber pressure.

[0062] Step 4), Growth Termination: After epitaxial growth for 40 seconds under the conditions of Step 3), the target thickness is about 10 nm. Stop the reaction gas silicon source and antimony doping source, and then cool down to below 600℃ to remove the epitaxial wafer, obtaining a uniformly antimony-doped selective epitaxial wafer.

[0063] Example 5

[0064] In this embodiment, in vitro epitaxial growth is performed using an ASM EPI3200 300mm epitaxial furnace. The specific steps are as follows:

[0065] Step 1), Substrate preparation and loading: A 300mm diameter P-type silicon polished wafer is used as the substrate. The substrate is cleaned using standard RCA and then transferred to the epitaxial furnace reaction chamber via a transfer cavity.

[0066] Step 2), Substrate pretreatment: Evacuate the reaction chamber to a base pressure <1.0×10⁻⁶. -5 Torr. In a pure H2 atmosphere, the substrate was baked at 1110°C for 30 seconds to remove the natural oxide layer on the surface.

[0067] Step 3), Epitaxial Growth: The reaction chamber pressure is set to 100 Torr, with high pressure to promote the growth rate; the substrate temperature is set to 1100℃; dichlorosilane (DCS) silicon source gas is introduced at a flow rate of 800 sccm, with high flow rate matching high growth rate; simultaneously, antimony doping sources SbH3 and SbCl3 are introduced, and the two are directly mixed in the reaction chamber nozzle at a molar ratio of 1:10, with SbCl3 dominating to suppress SbH3 decomposition; the total antimony atom flow rate is 300 sccm, which is used for a heavy doping concentration of approximately 1e19 atoms / cm. 3 The carrier gas is high-purity H2, and the total gas flow rate is automatically controlled by the equipment based on the reaction chamber pressure.

[0068] Step 4), Growth Termination: After epitaxial growth for 15 minutes under the conditions of Step 3), the target thickness is about 4.5 μm. Stop the reaction gas silicon source and antimony doping source, and then cool down to below 600℃ and remove it.

[0069] In this embodiment, a high SbCl3 ratio effectively "dilutes" SbH3 at high temperatures, preventing gas-phase pre-decomposition and particle defects. The expected growth rate reaches 400 nm / min, with thickness uniformity <5% and resistivity uniformity within the wafer <10%. Defect density is low, and there are no slip lines. This embodiment demonstrates the feasibility of the present invention's technical solution in thick-layer, heavily doped scenarios.

[0070] The above embodiments are intended to illustrate the essential content of the present invention, but are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of protection of the present invention.

Claims

1. A method for performing antimony-doped epitaxy on a silicon substrate, characterized in that, The method is carried out in a CVD epitaxial reactor, using a mixed gas of SbH3 and SbCl3 as the antimony doping source, and includes the following steps: a) Silicon substrate preparation and loading: Provide a clean silicon substrate and load it into the reaction chamber of the epitaxial furnace; b) Reaction chamber pretreatment and substrate preheating: The reaction chamber is evacuated to a high vacuum and the substrate is baked at high temperature in a hydrogen atmosphere to remove the natural oxide layer on the surface and obtain a clean silicon surface. c) Epitaxial growth and doping: A silicon source gas and a mixed gas of SbH3 and SbCl3 are introduced into the reaction chamber as an antimony doping source, and antimony-doped epitaxial growth is performed on the surface of the silicon substrate, wherein: The pressure in the reaction chamber was controlled between 5 Torr and 100 Torr. The substrate temperature is controlled between 600°C and 1100°C; The molar mixing ratio of SbH3 and SbCl3 is controlled between 1:10 and 10:1; d) Growth Termination: After the target epitaxial layer thickness is reached, stop the introduction of silicon source and antimony doping source gas, cool down and remove the epitaxial wafer.

2. The method for antimony-doped epitaxy on a silicon substrate according to claim 1, characterized in that, The reaction chamber pressure is set according to the target epitaxial layer type: For selective epitaxy, the reaction chamber pressure is set between 5 Torr and 50 Torr; For in vitro epitaxial growth, the reaction chamber pressure is set between 50 Torr and 100 Torr.

3. The method for antimony-doped epitaxy on a silicon substrate according to claim 1, characterized in that, The molar mixing ratio of SbH3 and SbCl3 is 1:3 to 3:

1.

4. The method for antimony-doped epitaxy on a silicon substrate according to claim 1, characterized in that: When the substrate temperature is between 600°C and 750°C, the molar mixing ratio of SbH3 and SbCl3 is greater than 1:

1.

5. The method for performing antimony-doped epitaxy on a silicon substrate according to claim 1, characterized in that: When the substrate temperature is between 900°C and 1100°C, the molar mixing ratio of SbH3 and SbCl3 is less than 1:

1.

6. The method for performing antimony-doped epitaxy on a silicon substrate according to claim 1, characterized in that: The silicon source gas is dichlorosilane or trichlorosilane, with a flow rate controlled in the range of 100 sccm to 1000 sccm, and works synergistically with the chlorine component in the antimony doping source.

7. The method for performing antimony-doped epitaxy on a silicon substrate according to claim 1, characterized in that: The total flux of the antimony doping source is from 1 sccm to 500 sccm, depending on the target doping concentration of 1×10⁻⁶. 15 atoms / cm 3 Up to 1×10 19 atoms / cm 3 Set within the range.

8. The method for performing antimony-doped epitaxy on a silicon substrate according to claim 1, characterized in that: The high-temperature baking in step b) is performed at a temperature of 800°C to 1100°C for 10 to 60 seconds, with a vacuum level below 1.0 × 10⁻⁶. - 5 Torr.

9. An antimony-doped silicon epitaxial layer, characterized in that, The epitaxial layer is prepared by the method described in any one of claims 1-8.

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