High electron mobility transistor (HEMT) and pseudomorphic high electron mobility transistor (PHEMT) devices with single layer integrated metal

摘要

A periodic table group III-IV HEMT/PHEMT field-effect transistor device and its fabrication is described. The disclosed fabrication arrangement uses a single metallization for ohmic and Schottky barrier contacts, employs selective etching with a permanent etch stop layer, employs a non-alloyed ohmic contact semiconductor layer and includes a permanent non photoresponsive secondary mask element affording several practical advantages during fabrication and in the completed transistor. The invention includes provisions for both an all- optical lithographic fabrication process and a combined optical and electron beam lithographic process. These concepts are combined to provide a field- effect transistor device of reduced fabrication cost, increased dimensional accuracy and state of the art electrical performance.