Patent ID: 6838325

Claim:
A method for forming a double recess high electron mobility transistor, comprising: providing a semiconductor structure having a III-V substrate; a wide band gap layer; a small band gap channel layer; a wideband gap Schotitky contact layer; an etch stop layer; a first wide band gap layer; and a ohmic contact layer; providing a mask, such mask having a second gate contact aperture to expose a gate region of the ohmic contact layer; bringing a first wet chemical etch into contact with portions of the ohmic contact layer exposed by the gate contact aperture, such etch selectively removing exposed portions of the ohmic contact layer and underlying portions of the second wide band gap layer, such etch stop layer inhibiting such etch from removing portions of such etch stop layer; bringing a second wet chemical etch into contact with said structure etched by the first wet etch, such second etch selectively removing exposed portions of the ohmic contact layer while leaving substantially un-etched exposed portions of the second wide band gap and the etch stop layer; and removing the etch stop layer; depositing a metal layer over the mask and through gate aperture therein onto, and in Schottky contact with the Schottky contact layer.