Investigation of molecular beam epitaxial growth of compound semiconductors and contacts for microwave devices

MBE growth of non-alloyed ohmic contacts using a 250 A layer of N+ germanium between the N type GaAs and the metal has yielded specific contact resistances well below 1 x 10 to the -7th power ohms/sq cm. Various N type dopants in GaAs were investigated; Si proved to be the best for making ultra thin doped or undoped donor regions, with Ge being nearly as good, except for a small amount of surface segregation. Beryllium proved to be the best for making ultra thin acceptor regions, and it was used to make the first planar doped barriers, constructed at Ft. Monmouth. The physical electronics of Ga,InAs/InP, with A1, InAs electron confining layers, show promise for high frequency transistors.