Electron beam and ion beam fabricated microwave switch

A combination of electron beam and ion beam techniques were used in conjunction with conventional planar technology to fabricate a junction field-effect microwave switch. A digital tape-controlled scanning electron beam was used to expose mask patterns in polymethyl methacrylate resist whose line widths (≤1 um) are inaccessible to conventional photolithography; ion beam sputtering was used to remove a thin gold undercoat from within the exposed patterns, thereby maintaining the good edge resolution; and ion implantation was used to dope the closely spaced interdigitated source and drain regions thus exposed by the preceding process steps in the gold contact mask.