Oxidation induced fault inhibition method and system for monocrystalline silicon rapid heat treatment process

Abstract

The invention relates to the technical field of semiconductor processing, in particular to an oxidation induced fault suppression system for a monocrystalline silicon rapid heat treatment process, comprising: an RTP reaction chamber having an outer reaction chamber and a quartz reaction chamber arranged therein; the heating unit is provided with an upper heating unit and a lower heating unit which are respectively positioned at the top and the bottom of the quartz reaction cavity; the gas path structure is provided with an upper-layer process gas pipeline and a lower-layer process gas pipeline which are connected to the interior of the quartz reaction cavity, high-purity argon is introduced into the upper layer, nitrogen-hydrogen mixed gas is injected into the lower layer, and oxygen readsorption is inhibited through gas layering; the in-situ monitoring module is arranged on the lower side of the quartz reaction cavity and is used for monitoring the crystal temperature gradient and the oxygen precipitation density.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material processing technology, specifically to a method and system for suppressing oxidation-induced stacking faults in a rapid thermal processing technology for single-crystal silicon. Background Technology

[0002] In Czochralski (CZ) single-crystal silicon growth, oxidation-induced stacking faults (OISFs) formed by the combination of oxygen atoms (Oi) and vacancies are critical defects affecting device performance. Traditional annealing processes suffer from problems such as unstable temperature gradients and low precision in oxygen precipitation control. Even with thermal field optimization to reduce oxygen content, it remains difficult to dynamically control vacancy distribution. Rapid thermal processing (RTP) technology, due to its rapid heating and cooling characteristics, can control defect dynamics at the nanoscale, achieving directional annihilation of oxygen atom-vacancy complexes and suppressing OISF formation at its source. Therefore, it is necessary to design a scheme that utilizes rapid thermal processing technology to suppress oxidation-induced stacking faults. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and system for suppressing oxidation-induced stacking faults in a rapid thermal processing technology for single-crystal silicon.

[0004] The technical solution of this invention is: An oxidation-induced stacking fault suppression system for rapid thermal processing of single-crystal silicon includes: The RTP reaction chamber has an outer reaction chamber and a quartz reaction chamber disposed therein; The heating unit has an upper heating unit and a lower heating unit, which are located at the top and bottom of the quartz reaction chamber, respectively; The gas path structure has an upper process gas pipeline and a lower process gas pipeline connected to the inside of the quartz reaction chamber. High-purity argon is introduced into the upper layer, and a nitrogen-hydrogen mixture is injected into the lower layer. Oxygen re-adsorption is suppressed through gas stratification. The in-situ monitoring module is located on the lower side of the quartz reaction chamber and is used to monitor the crystal temperature gradient and oxygen precipitation density.

[0005] Both the upper and lower heating units employ high-frequency induction coils, with a heating rate ≥800℃ / s.

[0006] The in-situ monitoring module includes an infrared thermal imager and an X-ray diffractometer.

[0007] The purity of the high-purity argon gas is ≥99.999%, and the hydrogen content in the nitrogen-hydrogen mixture is 1-3%.

[0008] Another technical solution of the present invention is: a method for suppressing oxidation-induced stacking faults in a rapid thermal processing technology for single-crystal silicon, employing the aforementioned oxidation-induced stacking fault suppression system, comprising: S1, Heating stage: The temperature of the monocrystalline silicon is raised to 1150-1250℃ at a heating rate of 50℃ / s, and the hydrogen flow rate is 7.5±1 SLM. S2, Processing stage: Apply RTP treatment at 1150-1250℃ to the surface of monocrystalline silicon for 5-30 seconds to form a surface vacancy depletion layer; S3. Post-processing stage: Cool down at a rate of 50℃ / s, quickly pass through the temperature range of OISF nucleation, and after dropping to 800℃, cool down to room temperature at a rate of 20℃ / s to eliminate residual thermal stress.

[0009] Preferably, in S2, the RTP processing maintains temperature-time coordination: the RTP peak temperature is higher than 90% of the silicon melting point, and the duration is less than 15 seconds, to avoid excessive introduction of lattice distortion.

[0010] Compared with the prior art, the present invention has the following advantages: This invention utilizes upper and lower heating units to achieve RTP processing, which breaks the oxygen-vacancy binding path, reducing the OISF density by more than 80%. This invention is applicable to lightly boron-doped silicon wafers with oxygen content of 8-12 ppma, meeting the requirements for defect sensitivity during BCD.

[0011] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the system structure in an embodiment of the present invention.

[0014] Figure labels: 1. External reaction chamber; 2. Quartz reaction chamber; 3. Quartz pin; 4. Single crystal silicon; 5. Upper heating unit; 6. Upper process gas pipeline; 7. Lower process gas pipeline; 8. Lower heating unit; 9. In-situ monitoring module. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0016] like Figure 1As shown, this embodiment provides an oxidation-induced stacking fault suppression system for a rapid thermal processing technology of single-crystal silicon, comprising: The RTP reaction chamber has an outer reaction chamber and a quartz reaction chamber disposed therein, and the quartz reaction chamber is provided with several quartz pins for supporting single crystal silicon. The heating unit has an upper heating unit and a lower heating unit, which are located at the top and bottom of the quartz reaction chamber, respectively. Both the upper heating unit and the lower heating unit adopt high-frequency induction coils with a frequency of 1-5 MHz, covering the silicon ingot growth interface, supporting local rapid heating, and a heating rate ≥800℃ / s.

[0017] The gas path structure has an upper process gas pipeline and a lower process gas pipeline connected to the inside of the quartz reaction chamber. The upper layer is filled with high-purity argon gas (purity ≥99.999%), and the lower layer is filled with a nitrogen-hydrogen mixture (H2 content 1-3%). The gas stratification inhibits oxygen re-adsorption. The in-situ monitoring module 9, located on the lower side of the quartz reaction chamber, includes an infrared thermal imager and an X-ray diffractometer, used to monitor the crystal temperature gradient and oxygen precipitation density.

[0018] A method for suppressing oxidation-induced stacking faults in a rapid thermal processing technology for single-crystal silicon, employing the aforementioned oxidation-induced stacking fault suppression system, includes: S1, Heating stage: The temperature of the monocrystalline silicon is raised to 1150-1250℃ at a heating rate of 50℃ / s, and the hydrogen flow rate is 7.5±1 SLM. S2, Processing Stage: Apply RTP treatment at 1150-1250℃ to the surface of single-crystal silicon for 5-30 seconds to form a surface vacancy depletion layer; The RTP treatment process maintains temperature-time coordination: the peak temperature of RTP is higher than 90% of the melting point of silicon (1414℃) (approximately 1272℃), and the duration is less than 15 seconds to avoid excessive introduction of lattice distortion. The injected H2 content is controlled below 3% to prevent hydrogen atoms from penetrating the lattice and forming HO recombination defects; S3. Post-processing stage: Cool down at a rate of 50℃ / s, quickly pass through the temperature range of OISF nucleation, and after dropping to 800℃, cool down to room temperature at a rate of 20℃ / s to eliminate residual thermal stress.

[0019] Example 1 S1, Heating stage: The temperature of the monocrystalline silicon is raised to 1250℃ at a heating rate of 50℃ / s, and the hydrogen flow rate is 7.5SLM. S2, Processing stage: Apply RTP treatment at 1250℃ to the surface of single crystal silicon for 15 seconds to form a surface vacancy depletion layer; control the injected H2 content to 2% to prevent hydrogen atoms from penetrating into the lattice and forming HO recombination defects; S3. Post-processing stage: Cool to 800℃ at a cooling rate of 50℃ / s, and then cool to room temperature at a cooling rate of 20℃ / s.

[0020] In the examples, different locations on the crystal rod were selected, with OISF densities ranging from 30.8 to 192.3 ea / cm³. 2 Regardless of the specific process, after the above treatment, the OISF can be eliminated to 0, resulting in a significant improvement in product quality and uniformity.

[0021] Table 1 OISF elimination status after RTP treatment Crystal rod position (mm) Initial OISF density (ea / cm2) OISF density (ea / cm2) after RTP treatment 200 59.6 0 250 53.8 0 300 37.5 0 350 30.8 0 400 33.7 0 450 115.4 0 500 66.3 0 550 60.6 0 600 115.4 0 650 79.8 0 700 79.8 0 750 75.0 0 800 66.3 0 850 192.3 0 900 73.1 0 950 55.8 0 The above description is merely a preferred embodiment of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An oxidation-induced stacking fault suppression system for rapid thermal processing of single-crystal silicon, characterized in that, include: The RTP reaction chamber has an outer reaction chamber and a quartz reaction chamber disposed therein; The heating unit has an upper heating unit and a lower heating unit, which are located at the top and bottom of the quartz reaction chamber, respectively; The gas path structure has an upper process gas pipeline and a lower process gas pipeline connected to the inside of the quartz reaction chamber. High-purity argon is introduced into the upper layer, and nitrogen-hydrogen mixture is injected into the lower layer. Oxygen re-adsorption is suppressed through gas stratification. The in-situ monitoring module is located on the lower side of the quartz reaction chamber and is used to monitor the crystal temperature gradient and oxygen precipitation density.

2. The oxidation-induced stacking fault suppression system for the rapid thermal processing of single-crystal silicon according to claim 1, characterized in that, Both the upper and lower heating units employ high-frequency induction coils, with a heating rate ≥800℃ / s.

3. The oxidation-induced stacking fault suppression system for the rapid thermal processing of single-crystal silicon according to claim 1, characterized in that, The in-situ monitoring module includes an infrared thermal imager and an X-ray diffractometer.

4. The oxidation-induced stacking fault suppression system for the rapid thermal processing of single-crystal silicon according to claim 1, characterized in that, The purity of the high-purity argon gas is ≥99.999%, and the hydrogen content in the nitrogen-hydrogen mixture is 1-3%.

5. A method for suppressing oxidation-induced stacking faults in a rapid thermal processing technology for single-crystal silicon, employing the oxidation-induced stacking fault suppression system described in any one of claims 1-4, characterized in that, include: S1, Heating stage: The temperature of the monocrystalline silicon is raised to 1150-1250℃ at a heating rate of 50℃ / s, and the hydrogen flow rate is 7.5±1 SLM. S2, Processing stage: Apply RTP treatment at 1150-1250℃ to the surface of monocrystalline silicon for 5-30 seconds to form a surface vacancy depletion layer; S3. Post-processing stage: Cool down at a rate of 50℃ / s, quickly pass through the temperature range of OISF nucleation, and after dropping to 800℃, cool down to room temperature at a rate of 20℃ / s to eliminate residual thermal stress.

6. The method for suppressing oxidation-induced stacking faults in the rapid thermal processing of single-crystal silicon according to claim 5, characterized in that: In S2, the RTP processing maintains temperature-time coordination: the RTP peak temperature is higher than 90% of the silicon melting point, and the duration is less than 15 seconds, to avoid excessive introduction of lattice distortion.

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