Simplified fabrication method for high-performance FET

Claim 1

A method for producing a high-performance FET comprising the steps of: forming on a semi-insulating semiconductor substrate an N-type layer of the substrate material which will constitute the active channel of the FET; forming on the N-type layer an (N+) layer of the substrate material; forming on the (N+) layer an (N++) layer of lower bandgap material; cutting a channel through the (N++) lower-bandgap material and the (N+) semiconductor to form a gate channel along the top of the (N) layer of semiconductor; forming a layer of refractory metal on all exposed portions of the previous layers; forming a layer of metal on the refractory metal layer; using a common mask to delineate the areas which are to to be the gate, source and drain electrodes and forming a properly exposed photoresist layer under said comon mask; cutting through said exposed photoresist and metal layers to form metal source, gate and drain electrodes of the proper size; and cutting through the refractory metal in the gate channel region to remove the remaining refractory metal lying above the active channel except for a stalk under the gate electrode and a pair of vertical regions extending from the refractory metal layers lying under the metal source and drain electrodes to the top of the active channel layer.

Claim 2

A method for producing a high-performance FET comprising the steps of: forming on a semi-insulating semiconductor substrate an N-type layer of the substrate material which will constitute the active channel of the FET; forming on the N-type layer an (N+) layer of the substrate material; forming on the (N+) layer an (N++) layer of lower bandgap material; cutting a channel through the (N++) lower-bandgap material and the (N+) semiconductor to form a gate channel along the top of the (N) layer of semiconductor; forming a layer of refractory metal on all exposed portions of the previous layers; forming a layer of metal on the refractory metal layer; using a common mask to delineate the areas which are to to be the gate, source and drain electrodes and forming a properly exposed photoresist layer under said comon mask; cutting through said exposed photoresist and metal layers to form metal source, gate and drain electrodes of the proper size; and cutting through the refractory metal in the gate channel region to remove the remaining refractory metal lying above the active channel except for a stalk under the gate electrode and a pair of vertical regions extending from the refractory metal layers lying under the metal source and drain electrodes to the top of the active channel layer.