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EP0455832A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Ohmic electrode of n-type cubic boron nitride and method of forming the same

Assignee: Sumitomo Electric Industries Ltd
•
Filing: 1990-11-28
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Granted: —
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Expires: 2010-11-28
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Abstract

Abstract An ohmic electrode of n-type cubic boron nitride comprises at least two thin layers, the first composed of one alloy or more of Au-Si, Au-Ge and Au-Si-Ge and the second composed of Ni, Cr, Mo, Pt and/or an alloy of these. The amt. of Si, Ge or the sum of Ge and Si is 0.1-35 wt.%. Producing the ohmic electrode comprises coating (1) a thin layer made of Au-Si, Au-Ge or Au-Si-Ge alloy on an n-type cubic boron nitride crystal. (2) A second thin layer made of Ni, Cr, Mo, Pt or an alloy of these is coated on the first layer. (3) The layers are heat treated in a vacuum or an inert gas atmos. at 350-600 deg.C (pref. 400-550 deg.C). The first and second thin layers are coated by a vacuum deposition method. The thickness of the first layer lies between 1000 and 3000 Angstroms, and of the second layer between 200 and 2000 Angstrom. The second layer is pref. made of Ni or Cr.

Inventors

  • 👤 Katsuhito Itami Works Of Sumitomo Yoshida
  • 👤 Kazuwo Itami Works Of Sumitomo Tsuji

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-04 23:10
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0116; H10D62/00; H10D62/80; H10D62/85; H10D64/60; H10D64/62

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 52 words
An ohmic electrode for n-type cBN which electrode comprises two thin films, the first is at least one alloy selected from a group consisting of Au-Si alloy, Au-Ge alloy and Au-Si-Ge alloy, and the second is at least one metallic material selected from a group consisting of Ni, Cr, Mo and Pt.
Claim 2
Dependent Claim 28 words
An ohmic electrode for n-type cBN as claimed in claim (1), wherein the weight ratio of Si, Ge and Si plus Ge is from 0.1 to 35 %.
Claim 3
Dependent Claim 89 words
A process for producing an ohmic electrode for n-type cBN, which comprises the steps of; providing a thin alloy film of at least one alloy selected from the group consisting of Au-Si alloy, Au-Ge alloy and Au-Si-Ge alloy; providing a thin film of at least one metal selected from Ni, Cr, Mo and Pt on said thin film; and subjecting said n-type cBN having said films thus provided to a heat-treatment in an inert gas or in vacuum at a temperature ranging from 350 °C to 600 °C .
Claim 4
Dependent Claim 24 words
A process as claimed in claim (3), wherein the weight ratio of Si, Ge and Si plus Ge is from 0.1 to 35 %.
Claim 5
Dependent Claim 27 words
A process as claimed in claim (3), wherein the provision of said thin alloy film and thin metal film is carried out by a vacuum vapor deposition.
Claim 6
Dependent Claim 24 words
A process as claimed in claim (3), wherein said heat treatment is conducted at a temperature ranging from 400 °C to 550 °C .
Claim 7
Dependent Claim 32 words
A process as claimed in claim (3), wherein the thichness of said thin film of a metal selected from Ni, Cr, Mo and Pt is ranging from 200 to 2000 Å .
Claim 8
Dependent Claim 23 words
A process as claimed in claim (3), wherein the thickness of said thin alloy film is ranging from 1000 to 3000 Å .
Claim 9
Dependent Claim 20 words
A process as claimed in claim (3), wherein said thin film of a metal is selected from Ni and Cr.

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