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EP0077893A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Low-resistance ohmic contacts to n-type group III-V semiconductors

Assignee: International Business Machines Corp
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Filing: 1982-08-10
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Granted: —
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Expires: 2002-08-10
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Abstract

Abstract A low resistance ohmic contact to a layer (6) of n-type GaAs is made by first vapour depositing layers (8, 10, 12) of Ni, Au and Ge on the GaAs, followed by a layer (14) of SiO z . This structure is heated to a temperature of 450°C within ten seconds and the structure is maintained at that temperature for 30 seconds to form an alloy ohmic contact. The structure is then rapidly cooled by applying a heat sink (20) to the back surface (5) of the substrate (2) supporting the GaAs layer (6). The technique may be used to form ohmic contacts to other n-type Group III-V semiconductors. Ohmic contacts formed using this method exhibit a very fine, high density, uniform granular structure.

Inventors

  • 👤 Mordehai Heiblum
  • 👤 Marshall Ira Nathan

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 03:49
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0116

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 103 words
A method of making an ohmic contact to an N-type Group III-V semiconductor layer (6) supported on one surface of a substrate (2), the method comprising the successive steps of depositing a layer (8,10,12) of contact material on the semiconductor layer (6), heating the structure to cause the contact material to form an alloy contact to the semiconductor layer and rapidly cooling the structure and being characterised by the rapid cooling being effected by removal of heat from the opposite surface (5) of the substrate (2) to that supporting the semiconductor layer (6) by contacting said opposite surface with a heat sink (20).
Claim 2
Independent Claim 103 words
A method of making an ohmic contact to an N-type Group III-V semiconductor layer (6) supported on one surface of a substrate (2), the method comprising the successive steps of depositing a layer (8,10,12) of contact material on the semiconductor layer (6), heating the structure to cause the contact material to form an alloy contact to the semiconductor layer and rapidly cooling the structure and being characterised by the rapid cooling being effected by removal of heat from the opposite surface (5) of the substrate (2) to that supporting the semiconductor layer (6) by contacting said opposite surface with a heat sink (20).
Claim 3
Dependent Claim 18 words
A method as claimed in claim 1, in which the semiconductor layer is an N-type gallium arsenide layer.
Claim 4
Dependent Claim 18 words
A method as claimed in claim 2, in which the contact material consists of nickel, gold and germanium.
Claim 5
Dependent Claim 25 words
A method as claimed in claim 3, in which the contact material is covered with a layer of silicon dioxide prior to the alloying step.
Claim 6
Dependent Claim 33 words
A method as claimed in claim 3 or claim 4, in which the alloying step comprises heating the structure to a temperature in the range of 400°C to 500°C, for approximately 30 seconds.

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