| 摘要 |
PURPOSE:To obtain a highly reliable ohmic contact resistive to heat, by forming an N<++>Ge layer on an N-type GaAs substrate or an N-type GaAs layer and then entirely covering the N<++>Ge layer with a high-melting metal protection film. CONSTITUTION:A thin Ge film 2 highly doped with As is vapor deposited n an N-type GaAs substrate 1 to form an N<++>Ge/N-GaAs hetero junction. The thin Ge film 2 is patterned to form Ge islands 2a and 2b. The entire surface of the substrate 1 is covered with a high-melting metal protection film or a W-Al film 3 by means of spattering. The W-Al film 3 is then patterned such that the remained W-Al film portions 3a an 3b cover entirely the Ge islands 2a and 2b, respectively. The W-Al film portions 3a and 3b thus prevent As from being evaporated from the Ge islands 2a and 2b during a high temperature phase. Further, the W-Al film portions 3a and 3b also prevent the hetero interface of Ge/GaAs from being deteriorated during the high temperature phase and the Ge islands 2a and 2b from being deteriorated by O2.
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