Tunnel Diodes by Vapor Growth of Ge on Ge and on GaAs [Letter to the Editor]

In thee xperimental work reported here it habse en shown that degenerately doped n type Ge can be vapor-grown epitaxially on degenerately doped p-type Ge or GaAs substrates, yielding tunnel junctions in either case. The vapor growth was performed at a low temperature in order to minimize interdiffusion of impurities at the junction. However, it was found that some heat treatment (subsequent to the vapor-growth step) increased peak current densities. G -Ge junctions were further heat treated and peak current densities then decreased. Both P and As have been used to dope thvea por-grown Ge. Up to the present time, higher concentrations have been achieved with phosphorus. Since it has been observed in alloyed tunnel junctions that As doping will give better peak-to-valley ratios, and since all the As incorporated in vapor-grown Ge is electrically active, 10 further work is being done on As doping.