HIGH ELECTRON MOBILITY HETEROJUNCTION SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING

摘要

In a high electron mobility heterojunction semiconductor device a heterojunction is formed between an n-type AlGaAs layer 5 and an undoped GaAs layer 4. An undoped AlGaAs layer 3 is tormed between layer 6 and the device substrate 1.
The layer 3 prevents migration of impurities from the substrate 1 during heat treatment in the manufacture of the device, acts as a buffer layer, and provides a test layer for setting up optimum manufacturing conditions before formation of n-type AlGaAs layer 5.