Buried channel heterojunction field effect transistor.

摘要

A high transconductance field effect transistor is realized by controlling the doping level in a conducting channel buried beneath a heterointerface. In one exemplary embodiment, a channel comprising an undoped, high mobility, narrow band gap quantum well (13) in combination with an intermediate band gap layer (12) is formed beneath a heterointerface. The heterojunction interface is between a wide band gap layer (15) and the quantum well region (13). A charge sheet (14) having the same conductivity type as the wide bandgap layer is formed near the heterointerface. Advantageously, the transconductance is enhanced by conduction in the undoped filled quantum well region.