GAAS INTEGRATED CIRCUIT AND ITS MANUFACTURE

摘要

PURPOSE: To obtain a GaAs heterojunction field-effect transistor HFET in an integrated circuit by realizing a precise etching of a wafer for forming an enhancement HFET by an etching stop layer thereby obtaining an HFET structure where an essentially flat reliable metal part of a wafer can be formed. CONSTITUTION: A buffer layer 4 of a compound semiconductor material having a first band gap energy is grown and then followed by the growth of a first spacer layer 5 of a compound semiconductor material having a second band gap energy and a dope layer 6 of a compound semiconductor material having a second band gap energy. Subsequently, a first cap layer 8 of a compound semiconductor material having a first band gap energy is grown and then followed by the growth of an etch stop layer 9 of a compound semiconductor material having a third band gap energy and a second cap layer 10 of a compound semiconductor material having a first band gap energy. This method realizes a novel process for fabricating both enhancement and depletion HFETs having a constant threshold voltage and a self-alignment structure over the entire wafer.