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Method for improving purity of AlN monocrystals by using reducing gas

A single-crystal, high-purity technology, applied in the direction of single crystal growth, single crystal growth, chemical instruments and methods, etc., can solve the problems of serious light absorption, unfavorable preparation of optoelectronic devices, etc., to improve optical quality, expand the application of AlN crystal, The effect of reducing the content of impurity elements

Active Publication Date: 2019-01-11
PEKING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The impurities introduced by these processes will introduce defect energy levels in the AlN energy band, causing severe light absorption, which is unfavorable for the preparation of optoelectronic devices

Method used

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  • Method for improving purity of AlN monocrystals by using reducing gas
  • Method for improving purity of AlN monocrystals by using reducing gas

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Embodiment 1 graphite furnace purification AlN powder (using methane or acetylene)

[0034] 1) Furnace charging and ventilation:

[0035] Put the tantalum carbide crucible with high-purity AlN source powder into the furnace body and close the furnace body, vacuumize the furnace body environment to 1 Torr, and fill high-purity nitrogen gas to 500 Torr, and replace the atmosphere in the cavity by filling and pumping for 3 to 5 times. The last 1 vacuum up to 10 -4 Torr;

[0036] 2) The furnace body is inflated and maintained:

[0037] After stopping the vacuuming of the furnace body, feed high-purity nitrogen gas or a mixed gas of high-purity nitrogen gas / high-purity argon gas with a ratio range of 0.1 to 0.9 into the furnace body to form an ambient atmosphere and keep the total pressure of the chamber stable. The pressure range is 10~900Torr;

[0038] 3) Furnace heating up:

[0039] Select an appropriate temperature gradient (1-20°C / min) to raise the temperature and ...

Embodiment 2

[0048] Embodiment two graphite furnace growth AlN single crystal (using methane or acetylene)

[0049] 1) Furnace charging and ventilation:

[0050] Place the tantalum carbide crucible with AlN sintered body on the graphite furnace body and close the furnace body, vacuumize the furnace body environment to 1 Torr, and fill the high-purity nitrogen gas to 500 Torr, and replace the atmosphere in the chamber by filling and pumping for 3 to 5 times, and finally 1 time to vacuum up to 10 -4 Torr;

[0051] 2) The furnace body is inflated and maintained:

[0052] After stopping the vacuuming of the furnace body, feed high-purity nitrogen gas or a mixed gas of high-purity nitrogen gas / high-purity argon gas with a ratio range of 0.1 to 0.9 into the furnace body to form an ambient atmosphere and keep the total pressure of the chamber stable. The pressure range is 10~900Torr;

[0053] 3) Furnace heating up:

[0054] Select an appropriate temperature gradient (1-20°C / min) to raise the...

Embodiment 3

[0063] Embodiment Three tungsten furnace growth AlN single crystal (using ammonia or hydrogen)

[0064] 1) Furnace charging and ventilation:

[0065] Place the tungsten crucible with AlN sintered body on the tungsten furnace body and close the furnace body, vacuumize the furnace body environment to 1 Torr, and fill high-purity nitrogen gas to 500 Torr, and replace the atmosphere in the cavity by filling and pumping for 3 to 5 times, and finally 1 Vacuum up to 10 times - 4 Torr;

[0066] 2) The furnace body is inflated and maintained:

[0067] After stopping the vacuuming of the furnace body, feed high-purity nitrogen gas or a mixed gas of high-purity nitrogen gas / high-purity argon gas with a ratio range of 0.1 to 0.9 into the furnace body to form an ambient atmosphere and keep the total pressure of the chamber stable. The pressure range is 10~900Torr;

[0068] 3) Furnace heating up:

[0069] Select an appropriate temperature gradient (1-20°C / min) to raise the temperature...

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Abstract

The invention discloses a method for improving the purity of AlN monocrystals by using a reducing gas. The method is characterized in that a lightly-doped active atmosphere technology is adopted, andan active gas having a strong reducing property at a high temperature is used as an atmosphere; a tiny amount of the active gas is introduced in a stepwise manner in the powder purification and monocrystal growth stage during physical vapor phase transportation in order to carry out light doping; and the active gas and impurity elements undergo a reduction reaction at a high temperature in the heating powder purification stage and the high-temperature monocrystal growth stage in order to remove impurity elements and grow high-purity AlN crystals. The method reduces the time and the cost, so the impurity content of the AlN monocrystals is significantly reduced, thereby the optical quality of an AlN substrate is improved, and the application of the AlN crystals is expanded.

Description

technical field [0001] The invention relates to the technical field of crystal growth, in particular to a method for improving the purity of AlN single crystals by using reducing gas. Background technique [0002] Because of its lattice constant and thermal expansion coefficient are very close to AlGaN with high Al composition, AlN single crystal can significantly improve the lattice quality of the epitaxial layer and reduce the defect density, thereby improving the internal quantum efficiency of the device. Optimal substrates for devices, including deep-UV LEDs and deep-UV detectors. At the same time, AlN single crystal has many advantages, including high breakdown field strength, high thermal conductivity, high hardness, and excellent electrical properties, which make it play an important role in high-temperature and high-frequency power electronic devices. To obtain high-quality AlN single crystals, the physical vapor transport method (PVT method) is currently the world'...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B23/02C30B29/40
CPCC30B23/02C30B29/403
Inventor 于彤军赵起悦吴洁君朱星宇李孟达韩彤沈波
Owner PEKING UNIV
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