| 摘要 |
A technique is described that provides a method for forming a p-type ohmic contact of a hetero-junction bipolar transistor. The method includes the steps of (A) sequentially forming a buffer layer 7, subcollector layer 6, collector 5, base layer 4, spacer layer 3, emitter layer 2 and capping layer 1 on a semi-insulating AlGaAs substrate 8, (B) depositing an emitter metal 9 on the capping layer 1 and then mesa-etching the capping layer 1 to the surface of the base layer 4 using the emitter metal 9 as a mask, (C) forming a p-type base metal 10 by sequentially depositing a first cromium metal layer 11, an AuZn alloy layer 12, second cromium metal layer 13, Pd metal layer 14 and Au metal layer 15 on the etched base layer 4, and (D) continuously covering the entire substrate 8 with a silicon oxide layer 16 and silicon nitride layer 17. Thereby, it is possible to improve the characteristic of the p-type ohomic contact.
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