Selective area chemical beam epitaxial regrowth of Si-doped GaAs by using silicon tetraiodide for field effect transistor application

Selective area regrowth of silicon-doped GaAs has been successfully achieved by chemical beam epitaxy (CBE) on dry etched trench structures. Abrupt doping-interface and excellent doping controllability have also been achieved by using a novel silicon dopant source of silicon tetraiodide (SiI4). Metal-semiconductor field effect transistor (MESFET) and heterostructure field effect transistor (HFET) fabricated in this way with Ni/AuGe/Au alloyed contact contact metals on the Si-doped GaAs regrown layer reveal contact resistances as low as 3 × 10− 7 Ω cm2 and perfect selectivity there being no polycrystalline growth on the dielectric mask film.