CARBON DOPING OF INSB USING CBR4 DURING GROWTH BY GAS-SOURCE MOLECULAR-BEAM EPITAXY

Carbon doping of epitaxial InSb films grown by gas-source molecular be am epitaxy was studied using carbon tetrabromide as the carbon dopant source. Carbon was found to be a p-type dopant in InSb, yielding the h ighest as-grown acceptor concentrations to date, up to mid 10(20) cm(- 3) as deposited. Room temperature mobilities ranged from 35 to 90 cm(2 )/V s depending upon doping level. The hole concentration was found to be relatively insensitive to growth temperature between 325 and 400 d egrees C. Higher growth temperatures required higher Sb fluxes in orde r to maintain a constant hole concentration. Hole concentration increa sed linearly with increasing CBr4 up to 5 X 10(20) cm(-3). Further inc rease in the dopant flow reduced the hole concentration and mobility a nd produced polycrystalline material. (C) 1998 American Institute of P hysics. [S0003-6951(98)02510-8].