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Method for obtaining high-quality silicon carbide surfaces

A technology of silicon carbide and single crystal silicon carbide, applied in chemical instruments and methods, single crystal growth, crystal growth, etc., can solve problems such as polysilicon, surface carburization, uniformity of gas doping, and difficult control of hydrogen corrosion temperature

Active Publication Date: 2014-11-05
BEIJING TIANKE HEDA SEMICON CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] (2) When pure hydrogen is used, the hydrogen etching speed is too fast, generally under low pressure, and there are many defects and surface impurities after hydrogen etching;
[0012] (4) When hydrogen is used to dope hydrocarbons, due to the influence of environmental factors, the uniformity of the doped gas and the hydrogen corrosion temperature are not easy to grasp; it is generally easy to cause surface carburization or surface polysilicon

Method used

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  • Method for obtaining high-quality silicon carbide surfaces
  • Method for obtaining high-quality silicon carbide surfaces
  • Method for obtaining high-quality silicon carbide surfaces

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Single crystal 4H-SiC (0001) silicon surface after cleaning with acetone, absolute ethanol and hydrofluoric acid to remove surface oxides and other pollutants, see surface morphology figure 1 , placed in a graphite crucible, the graphite crucible is placed in the heating cylinder of the intermediate frequency induction furnace, covered with graphite felt, to ensure that the temperature in the crucible can reach about 1580 °C when heated with a power of 5.7kw, and remain unchanged. The hydrogen etching process is carried out in the following three steps.

[0041] The first step to remove air: vacuum to a pressure of 10 -3 Pa; then filled with high-purity argon to 90kPa, and then vacuumed to 10 -3 Pa, kept for 5 minutes, filled with hydrogen-argon mixed gas (hydrogen 5Vol% + argon 95Vol%) to 20kPa.

[0042] The second step of hydrogen filling and corrosion: evacuate to 5kPa, and raise the temperature to 1580°C, then fill with hydrogen and argon mixed gas until the press...

Embodiment 2

[0046] After cleaning with acetone, absolute ethanol and hydrofluoric acid, the single crystal 6H-SiC(000-1) carbon surface after removing surface oxides and other pollutants is placed in a graphite crucible, and the graphite crucible is placed in an adjustable vacuum medium frequency induction furnace. Use hydrogen-argon mixed gas (hydrogen 5Vol% + argon 95Vol%) to wash the gas. After three times of washing, fill the hydrogen-argon mixed gas, keep the flow rate at 20sccm, and raise the temperature to 1600°C within 8 hours. Change to 1000 sccm, hydrogen etch for 1.5 hours and then cool with the furnace. The processed samples such as image 3 As shown, steps can be clearly observed on the surface, with a step height of 1.5 nm and a width of 40 nm to 100 nm.

Embodiment 3

[0048] After cleaning with acetone, absolute ethanol and hydrofluoric acid to remove surface oxides and other pollutants, the semi-insulating high-resistance single crystal 4H-SiC, after the silicon surface is ground, is placed in a graphite crucible, and the graphite crucible is placed in the No. 1 crystal The heating cylinder of the growth furnace is covered with graphite felt to ensure that the temperature in the crucible can reach about 1580°C when heated with a power of 5.7kw and remain unchanged. The following hydrogen etching process is carried out in three steps.

[0049] The first step of washing the furnace: vacuuming to a pressure of 10 -3 Pa; then filled with high-purity argon to 90kPa, and then vacuumed to 10 -3 Pa, kept for 5 minutes, filled with hydrogen-argon mixed gas (hydrogen 5Vol% + argon 95Vol%) to 20kPa.

[0050] The second step of hydrogen etching: evacuate to 5kPa, and raise the temperature to 1580°C, then fill it with hydrogen-argon mixture until the...

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Abstract

The invention provides a method for forming atomic steps on surfaces of silicon carbide crystals. The method has the following beneficial effects: the basic flat surfaces are exposed to hydrogen to preserve heat after being ground or polished; and the flowing hydrogen carries out hydrogen attack on samples while reacting with a carbon crucible until the damages and scratches caused by machining on the surfaces are eliminated; periodic steps with atomic flatness can be formed on the surfaces through further hydrogen attack. Different from other corrosion methods, the hydrogen attack method has the following advantages: the surfaces of the samples obtained by the method are extraordinarily clean and neither deposition of residual carbon nor particles of residual silicon exist; the difference between carbon and silicon consumption speeds during high temperature hydrogen attack is fundamentally overcome by adjusting the hydrogen attack temperature and the hydrogen pressure; and as the method is not related to machining, new surface damages can not be further caused obviously.

Description

technical field [0001] The invention relates to a method for treating the surface of silicon carbide, in particular to a method for treating the surface of silicon carbide by hydrogen etching. After the silicon carbide surface is chemically cleaned, it is hydrogen-etched in a carbon crucible to obtain a periodic surface with atomic steps. It can be used to grow thin film materials epitaxially or as a seed crystal to grow large-sized single crystals. Background technique [0002] As a wide bandgap semiconductor, single crystal silicon carbide has the characteristics of high thermal conductivity and high electron mobility. It is often used as a substrate for growing thin films, such as carbon films, gallium nitride films, etc. It can also be used as a seed crystal to grow large-sized single crystals, such as silicon carbide and aluminum nitride. When used as a substrate for epitaxial thin films, epitaxial growth is highly dependent on the substrate, and small defects on the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B33/12C30B29/36
Inventor 陈小龙黄青松郭丽伟王锡铭郑红军
Owner BEIJING TIANKE HEDA SEMICON CO LTD