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Method for treating the surface of a silicon-carbide substrate including a removal step in which a modified layer produced by polishing is removed by heating under Si vapor pressure

外国特許コード F160008779
整理番号 KG0120-US01
掲載日 2016年8月3日
出願国 アメリカ合衆国
出願番号 201414897342
公報番号 20160118257
公報番号 9978597
出願日 平成26年6月6日(2014.6.6)
公報発行日 平成28年4月28日(2016.4.28)
公報発行日 平成30年5月22日(2018.5.22)
国際出願番号 JP2014003049
国際公開番号 WO2014199615
国際出願日 平成26年6月6日(2014.6.6)
国際公開日 平成26年12月18日(2014.12.18)
優先権データ
  • 特願2013-125020 (2013.6.13) JP
  • 2014WO-JP03049 (2014.6.6) WO
発明の名称 (英語) Method for treating the surface of a silicon-carbide substrate including a removal step in which a modified layer produced by polishing is removed by heating under Si vapor pressure
発明の概要(英語) (US9978597)
This method for treating a surface of a SiC substrate includes a first removal step in which a modified layer produced by subjecting the substrate (70) to mechanical polishing or chemical-mechanical polishing is removed by heating the substrate (70) under Si vapor pressure.
A second removal step in which macro-step bunching occurred in an epitaxial layer (71) is removed by heating the substrate (70) under Si vapor pressure may also be performed.
Since the etching rate can be varied, etching rate in the first removal step is high, so that the modified layer can be removed in a short time.
Meanwhile, etching rate in the second removal step is comparatively low, so that excessive removal of the epitaxial layer (71) can be prevented.
特許請求の範囲(英語) [claim1]
1. A method for treating a surface of a SiC substrate having an off angle, the substrate having at least its surface made of (0001) Si-face or (000-1) C-face, the method comprising: cutting the SiC substrate out of an ingot;
generating a modified layer in the SiC substrate by applying pressure to the surface of the substrate with mechanical polishing or chemical-mechanical polishing, said mechanical polishing or chemical-mechanical polishing causing polishing scratches on the surface of the SiC substrate with said modified layer inside the polishing scratches; and
performing a first removal step of removing a depth including about 10 mu m from the surface of the SiC substrate including removing the polishing scratches and the modified layer produced by subjecting the substrate to said mechanical polishing or chemical-mechanical polishing by heating the substrate under Si vapor pressure, wherein said first removal step includes performing isotropic etching, said isotropic etching being in a region above a boundary line in a graph logarithmically representing etching rate.
[claim2]
2. The method for treating the surface of the SiC substrate according to claim 1, wherein in the first removal step, heating is performed in a temperature range of 1800 deg. C. or more and 2300 deg. C. or less and under the Si vapor pressure of 10-2 Pa or more.
[claim3]
3. The method for treating the surface of the SiC substrate according to claim 1, the method comprising: performing a second removal step of removing macro-step bunching produced on an epitaxial layer formed on the surface of the substrate using a chemical vapor deposition process by heating the substrate under the Si vapor pressure.
[claim4]
4. The method for treating the surface of the SiC substrate according to claim 3, wherein in the second removal step, etching rate is lower than that of the first removal step and a depth of about several tens nm is removed from the surface of the SiC substrate.
[claim5]
5. The method for treating the surface of the SiC substrate according to claim 3, wherein in the second removal step, heating is performed in a temperature range of 1600 deg. C. or more and 2000 deg. C. or less, and under the Si vapor pressure of 10-3 Pa or less.
[claim6]
6. The method for treating the surface of the SiC substrate according to claim 3, wherein in consideration of the relationship between heating condition including the Si vapor pressure, heating temperature and etching rate and the presence or absence of occurrence of the macro-step bunching, the heating condition is determined in at least either one of the first removal step or the second removal step.
[claim7]
7. The method for treating the surface of the SiC substrate according to claim 6, wherein in further consideration of the off angle of the substrate, the heating condition is determined.
[claim8]
8. The method for treating the surface of the SiC substrate according to claim 1, wherein the surface of the substrate has an off angle of 4 degrees or less in the direction of <11-20>.
[claim9]
9. The method for treating the surface of the SiC substrate according to claim 1, wherein the surface of the substrate has an off angle of 4 degrees or less in the direction of <1-100>.
[claim10]
10. The method for treating the surface of the SiC substrate according to claim 1, wherein the surface of the substrate is terminated at a step having a full-unit height that corresponds to one periodic of SiC molecules in a stack direction or a half-unit height that corresponds to one-half periodic.
[claim11]
11. The method for treating the surface of the SiC substrate according to claim 1, wherein said removing in said first removal step is at a rate of about 100 nm/min or more.
[claim12]
12. The method for treating the surface of the SiC substrate according to claim 11, wherein said removing in said first removal step is at a rate of about 500 nm/min or more.
[claim13]
13. The method for treating the surface of the SiC substrate according to claim 1, wherein macro-step bunching does not occur in the region above the boundary line.
[claim14]
14. The method for treating the surface of the SiC substrate according to claim 13, wherein the macro-step bunching occurs in a region below the boundary line.
  • 発明者/出願人(英語)
  • KANEKO TADAAKI
  • OHTANI NOBORU
  • HAGIWARA KENTA
  • KWANSEI GAKUIN
国際特許分類(IPC)
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