ELECTRICAL-PROPERTIES OF HEAVILY SI-DOPED (311)A GAAS GROWN BY MOLECULAR-BEAM EPITAXY

We have systematically studied the electrical properties of heavily Si-doped GaAs grown on the (311)A GaAs surfaces by molecular beam epitaxy. It is found that the conduction type drastically changes from p type to n type with decreasing growth temperature at a critical temperature of approximately 430-degrees-C for uniform doping and approximately 480-degrees-C for the delta-doping case, with the transition temperature width as narrow as approximately 50-degrees-C for both cases. The highest hole density obtained for uniformly doped layers was 1.5 x 10(20) cm-3, while for delta-doped layers a sheet hole density as high as 2.6 x 10(13) cm-2 was achieved, which is the highest sheet bole density ever reported for delta-doped p-type GaAs.