Patent ID: 6100548
Filing Date: 2000-08-08
Classification: H01L

Abstract:
A field-effect transistor, comprising:a layered semiconductor structure which includes:a) a group III nitride compound first semiconductor layer having a first band gap and doped with a charge carrier;b) a group III nitride compound second semiconductor layer having a second band gap that is less than said first band gap and positioned below said first semiconductor layer to generate a two-dimensional electron gas in said semiconductor structure;c) a substrate which supports said first and second semiconductor layers;d) source and drain ohmic contacts which communicate with said two-dimensional electron gas; ande) a gate on said semiconductor structure between said source and drain ohmic contacts;a mesa defined in said layered semiconductor structure to isolate said gate, said source and drain ohmic contacts, said first semiconductor layer and said two-dimensional gas;a substantially vertical sidewall defined by said mesa and positioned proximate and substantially parallel to at least a portion of said gate, said sidewall exposing said first semiconductor layer, said two-dimensional electron gas and at least a portion of said second semiconductor layer;a passivation layer over said vertical sidewall; anda gate feed which passes over said passivation layers contacts said gate and is spaced from said vertical sidewall to thereby reduce capacitance between said gate feed and said two-dimensional gas.