CN112593293A - Heat treatment method of aluminum nitride wafer - Google Patents

Heat treatment method of aluminum nitride wafer Download PDF

Info

Publication number
CN112593293A
CN112593293A CN202011216155.0A CN202011216155A CN112593293A CN 112593293 A CN112593293 A CN 112593293A CN 202011216155 A CN202011216155 A CN 202011216155A CN 112593293 A CN112593293 A CN 112593293A
Authority
CN
China
Prior art keywords
aluminum nitride
wafer
heat treatment
nitride wafer
container
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202011216155.0A
Other languages
Chinese (zh)
Inventor
吴亮
王琦琨
雷丹
黄嘉丽
付丹扬
龚建超
刘欢
朱如忠
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aoti Photoelectric Technology Hangzhou Co ltd
Original Assignee
Aoti Photoelectric Technology Hangzhou Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aoti Photoelectric Technology Hangzhou Co ltd filed Critical Aoti Photoelectric Technology Hangzhou Co ltd
Priority to CN202011216155.0A priority Critical patent/CN112593293A/en
Publication of CN112593293A publication Critical patent/CN112593293A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
    • C30B33/02—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/40—AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
    • C30B29/403—AIII-nitrides

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

The invention aims to solve the problems of improving the crystal quality, the ultraviolet transmittance, the processing yield and the like of a wafer in the preparation of a high-difficulty aluminum nitride wafer, and provides a heat treatment method of the aluminum nitride wafer, which effectively improves the problems by carrying out heat treatment on the aluminum nitride wafer under a specific environment so as to improve the quality and the processing yield of the wafer. In order to achieve the purpose, the invention adopts the following technical scheme: an aluminum nitride wafer heat treatment method comprises the following steps: preparing a single piece or a plurality of pieces of aluminum nitride wafers; putting the aluminum nitride wafer into a container, and immediately putting the container into high-temperature equipment; the high-temperature equipment heats the container and keeps the temperature for a period of time, and the aluminum nitride wafer is subjected to heat treatment under the flowing of protective gas; and after the heat treatment and heat preservation are finished, cooling to room temperature, and taking out the aluminum nitride wafer.

Description

Heat treatment method of aluminum nitride wafer
Technical Field
The invention relates to the technical field of semiconductors, in particular to a heat treatment method for an aluminum nitride wafer.
Background
The aluminum nitride as a third-generation wide bandgap semiconductor material has the advantages of high bandgap width (6.2ev), high thermal conductivity (340W/(m.K)), high breakdown field strength, good ultraviolet transmittance, chemical and thermal stability and the like, is an ideal ultraviolet photoelectron device material, can be widely applied to the fields of deep ultraviolet LEDs, ultraviolet curing, ultraviolet detectors and the like, and has wide application prospects. Because the AlN and the GaN crystal structure belong to the wurtzite structure, the lattice mismatch rate along the c surface is only 2.4 percent, which is superior to the existing mature and widely used sapphire and SiC substrate materials; on the other hand, the thermal expansion coefficients of AlN and GaN are the closest, and the mismatch of the thermal expansion coefficients is close to zero at the high temperature of 1000 ℃, so that the product yield of an epitaxial device structure caused by thermal stress in the cooling process can be avoided, and the substrate material is an ideal substrate material for epitaxially growing GaN/high-aluminum component AlGaN.
Numerous studies have shown that Physical Vapor Transport (PVT) is the most efficient method for growing large-size aluminum nitride single crystals in bulk. Compared with the process of epitaxially growing large-size aluminum nitride films (metal organic compound vapor phase epitaxy, molecular beam epitaxy, hydride vapor phase epitaxy, and the like), the aluminum nitride crystal prepared by the PVT method has lower dislocation density (<106cm-2) Higher crystal quality (FWHM for 0002-XRD rocking curve)<100 arcsec). However, the PVT process has a high technical barrier to AlN, resulting in only a few international entities currently having the ability to produce high quality AlN wafers. At present, the international small-size (1/2inch) aluminum nitride substrate is grown and produced in small batches, and the quality of the prepared wafer and the processing yield thereof reach oneDetermining the sustainable development level. However, in order to further improve the quality of the ingot/wafer and the processing yield thereof, and to achieve stable production efficiency and market supply in large quantities, further optimization and solution of the problems of the crystal quality, the ultraviolet transmittance, the impurity concentration, the mixed polarity and the like of the ingot/wafer are urgently needed.
Therefore, the invention provides a heat treatment method of an aluminum nitride wafer, aiming at the problems, the heat treatment can promote the combination of crystal grains in the AlN crystal to improve the crystallization quality, reduce the concentration of Al vacancy and further improve the ultraviolet transmittance under the protective gas and high-temperature environment, and provides a technical scheme with good effect, high repeatability and high stability for improving the quality of the AlN wafer.
Disclosure of Invention
The invention aims to solve the problems of improving the crystal quality, the ultraviolet transmittance, the processing yield and the like of a wafer in the preparation of a high-difficulty aluminum nitride wafer, and provides a heat treatment method of the aluminum nitride wafer, which effectively improves the problems by carrying out heat treatment on the aluminum nitride wafer under a specific environment so as to improve the quality of the wafer.
In order to achieve the purpose, the invention adopts the following technical scheme:
an aluminum nitride wafer heat treatment method comprises the following steps:
s1, preparing single or multiple aluminum nitride wafers;
s2, placing the aluminum nitride wafer into a container, and then placing the container into high-temperature equipment;
s3, heating and keeping the temperature of the container for a period of time by the high-temperature equipment, and carrying out heat treatment on the aluminum nitride wafer under the flowing of protective gas;
and S4, cooling to room temperature after the heat treatment and heat preservation are finished, and taking out the aluminum nitride wafer.
In a preferred embodiment, in step S3, the heat preservation temperature is 1400 to 1900 ℃, and the heat preservation time is 0.5 to 100 hours.
In a more preferred embodiment, in step S3, the heat preservation temperature is 1700 to 1800 ℃, and the heat preservation time is 1 to 20 hours.
Through the process, the solid phase reaction in the wafer is beneficial to eliminating the boundary of the domain between the grains, promoting the combination between the grains, eliminating the residual stress and reducing the dislocation density. Meanwhile, impurities in the wafer are diffused, so that the impurity concentration is reduced, the aluminum vacancy concentration is reduced, and the wafer quality and the ultraviolet transmittance are improved.
As an alternative embodiment, in step S3, the protective gas is nitrogen, argon, ammonia, hydrogen or carbon monoxide, and the pressure of the protective gas is 0.01 to 10 bar.
In a preferred embodiment, the protective gas is nitrogen, and the pressure of the protective gas is 0.8-2 bar.
At lower temperatures and higher nitrogen pressures, the equilibrium nitrogen vacancy concentration is much lower. Thus, by performing the heat treatment at a certain temperature, solid state diffusion can occur to reduce the aluminum vacancy concentration.
Alternatively, in step S1, the aluminum nitride wafer is a single aluminum nitride wafer or a multi-aluminum nitride wafer or a bulk aluminum nitride.
As an alternative embodiment, in step S2, the container is made of a high temperature resistant metal, alloy or ceramic material, and the resistant temperature is 1400-1900 ℃.
As an alternative embodiment, the refractory metal, alloy or ceramic material includes, but is not limited to, tungsten, molybdenum, tantalum carbide, graphite, carbon fiber, zirconia, silicon carbide or aluminum nitride.
Alternatively, in step S3, the high temperature device heats the container by resistive heating or inductive heating or a combination of resistive heating and inductive heating.
The invention also provides an aluminum nitride wafer obtained by heat treatment by using the method.
The invention has the following beneficial technical effects:
the method can effectively improve the crystallization quality and the ultraviolet transmittance of the aluminum nitride wafer with high difficulty in preparation by carrying out heat treatment on the aluminum nitride wafer in a specific environment, reduce the impurity concentration and release the residual stress in the crystal, thereby improving the qualification rate of the wafer for cutting and polishing. Meanwhile, the process method disclosed by the invention has the advantages of good implementation effect, high repeatability and high stability, is beneficial to the large-scale production of high-quality products of the aluminum nitride wafer, and meets the commercial requirements for large-scale preparation and production of high-quality and large-size aluminum nitride substrates.
Drawings
FIG. 1 is a schematic view of an AlN wafer and a container assembled together according to an embodiment of the present invention.
FIG. 2 is a process diagram of an embodiment of the present invention.
FIG. 3 is a comparison of AlN wafers before and after heat treatment in examples of the present invention.
FIG. 4 is a comparison graph of HRXRD rocking curve detection results before and after the AlN wafer is subjected to the heat treatment in the example of the present invention.
FIG. 5 is a comparison graph of the results of the UV absorption coefficient measurements of AlN wafers before and after heat treatment in the examples of the present invention.
Detailed Description
The present invention is further described with reference to the following embodiments. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. It should be noted that variations and modifications can be effected without departing from the spirit of the invention, which is within the scope of the invention as defined by the appended claims.
FIG. 1 is a schematic view showing the assembly of an AlN wafer with a container in the embodiment of the present invention, which may be a single-piece assembly as shown in FIG. 1(a), or a multi-piece assembly as shown in FIG. 1 (b). The following description will be made by taking the single-piece assembly as an example.
As shown in fig. 1(a), a single piece of 1inch diameter AlN wafer 3 was prepared, assembled in a pure tungsten container 2, and the container lid 1 was closed, leaving a vent hole in the pure tungsten container 2 to facilitate the flow of the shielding gas through the container.
Reference is made to the process diagram shown in figure 2. In a preferred embodiment, the assembled container is first placed in a high temperature apparatus, which is evacuated to 10 deg.f-5pa or less.Heating the container to a target temperature T1(1800 ℃), and simultaneously charging high purity N before and after the target temperature is reached2The heat treatment was carried out under a gas pressure P1(1bar) and at this temperature for 10 h. And after the heat treatment is finished, cooling and vacuumizing are performed simultaneously, so that the AlN wafer 3 is prevented from being polluted by other impurities. After cooling to room temperature, the AlN wafer 3 is taken out. FIG. 3 is a schematic comparison of AlN wafers 3 before and after heat treatment. Three-dimensional defects influenced by impurities can be seen in the AlN wafer before heat treatment, and the defects in the AlN wafer after heat treatment are eliminated, so that the wafer is more transparent. The above phenomenon is due to the diffusion and reduction of impurities inside the AlN wafer during the heat treatment, and the associated defects are improved.
FIG. 4 shows the HRXRD rocking curve characterization results of the AlN wafer 3 before and after the heat treatment. The crystallization quality of the AlN wafer after heat treatment is remarkably improved, the FWHM (full width at half maximum) of (002) diffraction plane is improved by about 31 percent, and the FWHM (full width at half maximum) of (102) diffraction plane is improved by about 39 percent, which shows that the heat treatment process has larger improvement on the quality of the AlN wafer.
FIG. 5 is a comparison of the results of characterization of the UV absorption coefficient of AlN wafer 3 before and after heat treatment. The ultraviolet transmittance of the AlN wafer 3 is remarkably improved after heat treatment, and the absorption coefficient of 265nm is lower than 20cm-1The heat treatment process achieves the world leading level, and shows that the heat treatment process has great improvement on the ultraviolet transmittance of the AlN wafer.
Table 1 below shows the comparison of the results of GDMS and EGA detection of impurity content before and after the AlN wafer 3 was subjected to heat treatment.
TABLE 1
Impurity content (PPMwt) C O Si
Before heat treatment 81 110 9.7
After heat treatment 20 95 6.3
It can be seen that the significant C, O, Si impurity content of AlN wafer 3 was significantly reduced after heat treatment, indicating that heat treatment can increase wafer purity and reduce point defects caused by impurities.
In conclusion, the method of the invention realizes the heat treatment of the single-chip/multi-chip AlN wafer, can improve the crystallization quality and the ultraviolet transmittance of the wafer, reduce the defect density, improve the integral quality uniformity of the wafer, and release the residual stress in the wafer, thereby improving the qualification rate of the wafer which is cut and polished. The technical scheme is beneficial to large-scale and commercial promotion of the quality of AlN wafers with various sizes. Moreover, the process scheme has high repeatability, high stability and obvious effect.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (10)

1. An aluminum nitride wafer heat treatment method comprises the following steps:
s1, preparing single or multiple aluminum nitride wafers;
s2, placing the aluminum nitride wafer into a container, and placing the container into high-temperature equipment;
s3, heating and keeping the temperature of the container for a period of time by the high-temperature equipment, and carrying out heat treatment on the aluminum nitride wafer under the flowing of protective gas;
and S4, cooling to room temperature after the heat treatment and heat preservation are finished, and taking out the aluminum nitride wafer.
2. The method according to claim 1, wherein in step S3, the holding temperature is 1400-1900 ℃ and the holding time is 0.5-100 h.
3. The method according to claim 2, wherein in step S3, the holding temperature is 1700-1800 ℃ and the holding time is 1-20 h.
4. The method according to claim 1, wherein in step S3, the protective gas is nitrogen, argon, ammonia, hydrogen or carbon monoxide, and the pressure of the protective gas is 0.01 to 10 bar.
5. The method according to claim 4, wherein the protective gas is nitrogen and the pressure of the protective gas is 0.8 to 2 bar.
6. The method according to any one of claims 1 to 5, wherein in step S1, the aluminum nitride wafer is a single aluminum nitride wafer or a multi-aluminum nitride wafer or a bulk aluminum nitride.
7. The method according to any one of claims 1 to 5, wherein in step S2, the container is made of a high temperature resistant metal, alloy or ceramic material, and the temperature resistance is 1400 ℃ and 1900 ℃.
8. The method of claim 7, wherein the refractory metal, alloy or ceramic material comprises, but is not limited to, tungsten, molybdenum, tantalum carbide, graphite, carbon fiber, zirconia, silicon carbide or aluminum nitride.
9. The method of any one of claims 1 to 5, wherein the high temperature device heats the container by resistive heating or inductive heating or a combination of resistive heating and inductive heating in step S3.
10. An aluminum nitride wafer heat-treated using the method as claimed in any one of claims 1 to 9.
CN202011216155.0A 2020-11-04 2020-11-04 Heat treatment method of aluminum nitride wafer Pending CN112593293A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011216155.0A CN112593293A (en) 2020-11-04 2020-11-04 Heat treatment method of aluminum nitride wafer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011216155.0A CN112593293A (en) 2020-11-04 2020-11-04 Heat treatment method of aluminum nitride wafer

Publications (1)

Publication Number Publication Date
CN112593293A true CN112593293A (en) 2021-04-02

Family

ID=75180565

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011216155.0A Pending CN112593293A (en) 2020-11-04 2020-11-04 Heat treatment method of aluminum nitride wafer

Country Status (1)

Country Link
CN (1) CN112593293A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113668061A (en) * 2021-07-27 2021-11-19 奥趋光电技术(杭州)有限公司 Method for improving ultraviolet transmittance of aluminum nitride wafer

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006206343A (en) * 2005-01-25 2006-08-10 Ngk Insulators Ltd METHOD FOR FLATTENING SURFACE OF AlN SINGLE CRYSTAL AND METHOD FOR MANUFACTURING AlN SINGLE CRYSTAL SUBSTRATE
CN101454487A (en) * 2006-03-30 2009-06-10 晶体公司 Methods for controllable doping of aluminum nitride bulk crystals
TW201307193A (en) * 2011-08-04 2013-02-16 Chung Shan Inst Of Science Method for removing oxygen from aluminum nitride by carbon
JP2015042598A (en) * 2013-08-26 2015-03-05 国立大学法人東北大学 Substrate having aluminum nitride (ain) film and method for manufacturing aluminum nitride (ain) film
CN107768234A (en) * 2017-09-27 2018-03-06 中国科学院长春光学精密机械与物理研究所 A kind of method for obtaining high quality AlN templates
CN111164242A (en) * 2017-09-22 2020-05-15 株式会社德山 Group III nitride single crystal substrate
US20200190694A1 (en) * 2017-11-10 2020-06-18 Robert T. Bondokov Thermal control for formation and processing of aluminum nitride
CN111883651A (en) * 2020-07-23 2020-11-03 奥趋光电技术(杭州)有限公司 Method for preparing high-quality aluminum nitride template

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006206343A (en) * 2005-01-25 2006-08-10 Ngk Insulators Ltd METHOD FOR FLATTENING SURFACE OF AlN SINGLE CRYSTAL AND METHOD FOR MANUFACTURING AlN SINGLE CRYSTAL SUBSTRATE
CN101454487A (en) * 2006-03-30 2009-06-10 晶体公司 Methods for controllable doping of aluminum nitride bulk crystals
TW201307193A (en) * 2011-08-04 2013-02-16 Chung Shan Inst Of Science Method for removing oxygen from aluminum nitride by carbon
JP2015042598A (en) * 2013-08-26 2015-03-05 国立大学法人東北大学 Substrate having aluminum nitride (ain) film and method for manufacturing aluminum nitride (ain) film
CN111164242A (en) * 2017-09-22 2020-05-15 株式会社德山 Group III nitride single crystal substrate
CN107768234A (en) * 2017-09-27 2018-03-06 中国科学院长春光学精密机械与物理研究所 A kind of method for obtaining high quality AlN templates
US20200190694A1 (en) * 2017-11-10 2020-06-18 Robert T. Bondokov Thermal control for formation and processing of aluminum nitride
CN111630630A (en) * 2017-11-10 2020-09-04 晶化成半导体公司 Large-size ultraviolet transparent aluminum nitride single crystal and preparation method thereof
CN111883651A (en) * 2020-07-23 2020-11-03 奥趋光电技术(杭州)有限公司 Method for preparing high-quality aluminum nitride template

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113668061A (en) * 2021-07-27 2021-11-19 奥趋光电技术(杭州)有限公司 Method for improving ultraviolet transmittance of aluminum nitride wafer

Similar Documents

Publication Publication Date Title
EP2230332B1 (en) Silicon carbide single crystal ingot, and substrate and epitaxial wafer obtained from the silicon carbide single crystal ingot
US8410488B2 (en) Micropipe-free silicon carbide and related method of manufacture
JP5706823B2 (en) SiC single crystal wafer and manufacturing method thereof
US8871025B2 (en) SiC single crystals with reduced dislocation density grown by step-wise periodic perturbation technique
EP2487280A1 (en) Method for producing a 100 mm silicon carbide wafer with Low micropipe density
JP4926556B2 (en) Method for manufacturing silicon carbide single crystal ingot and silicon carbide single crystal substrate
JP4818754B2 (en) Method for producing silicon carbide single crystal ingot
JP4603386B2 (en) Method for producing silicon carbide single crystal
US10036099B2 (en) Process for large-scale ammonothermal manufacturing of gallium nitride boules
EP1852527B1 (en) Silicon carbide single crystal and silicon carbide single crystal wafer
JP4460236B2 (en) Silicon carbide single crystal wafer
CN115832018A (en) 4H-SiC epitaxial structure for controlling TSD defects and growth method
CN109183143B (en) Method for improving AlN single crystal purity by using reducing gas
JP5131262B2 (en) Silicon carbide single crystal and method for producing the same
CN112593293A (en) Heat treatment method of aluminum nitride wafer
CN111575794A (en) Low-stress silicon carbide crystal growth temperature field setting device and crystal growth method
CN110117814A (en) The preparation method of silicon carbide epitaxy with low-density C vacancy defect
JP4595592B2 (en) Single crystal growth method
JP2003137694A (en) Seed crystal for growing silicon carbide single crystal, silicon carbide single crystal ingot and method of producing the same
KR100821360B1 (en) Silicon carbide single crystal, silicon carbide single crystal wafer, and process for producing the same
CN113005518B (en) Method for preparing silicon carbide single crystal
JP4160769B2 (en) Silicon carbide single crystal ingot and wafer
TW202143303A (en) Method for producing semiconductor substrate, semiconductor substrate, and method for preventing crack occurrence in growth layer
CN115295412A (en) High-temperature rapid heat treatment process and device for silicon carbide device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20210402