Abstract: A method of fabricating a semiconductor device includes the steps of forming an insulation film on a compound semiconductor layer, forming an opening in the insulation film so as to expose a part of the compound semiconductor layer, forming a gate electrode of a refractory metal compound on the insulation film such that the gate electrode contacts with the compound semiconductor layer at the contact hole, and removing the insulation film by a wet etching process, wherein the wet etching process is conducted by an etchant to which both of the gate electrode and the compound semiconductor layer show a resistance.

Abstract: A method of fabricating a semiconductor device includes the steps of forming an insulation film on a compound semiconductor layer, forming an opening in the insulation film so as to expose a part of the compound semiconductor layer, forming a gate electrode of a refractory metal compound on the insulation film such that the gate electrode contacts with the compound semiconductor layer at the contact hole, and removing the insulation film by a wet etching process, wherein the wet etching process is conducted by an etchant to which both of the gate electrode and the compound semiconductor layer show a resistance.

Abstract: A semiconductor device comprises an active layer formed of a compound semiconductor for allowing carriers travel therethrough for exhibiting a function of the device, a protection layer including a non-doped compound semiconductor layer formed on the active layer, a pair of contact holes formed in the protection layer to expose the active layer, and an electrode filling the contact holes and covering the exposed active layer and extending on the protection layer. Generation of notch can be prevented even upon formation of a contact hole in the non-doped compound semiconductor layer and depositing electrode layer thereon.