Field effect transistor, compound semiconductor substrate and process for forming a recess therein

摘要

A III-V field effect transistor comprising a semiconductor channel layer having an electrically conducting channel; an ohmic contact layer on the semiconductor channel layer, the ohmic contact layer having a recess structure disposed therethrough to the semiconductor channel layer; the bottom of the ohmic contact layer comprising an etch stop layer comprising Aluminium and Phosphorous and defining the shape of the recess at its junction with the semiconductor channel layer.