Electron mobility enhancement in heavily doped GaAs:C heterojunction bipolar transistors

Magnetotransport methods are used to directly measure the electron mobility in the p GaAs base of heterojunction bipolar transistors grown by metal organic vapour-phase epitaxy. Enhancement of minority electron magnetotransport mobilities from 1400 to 2200 cm² V^-1 S¹ for hole concentrations from 0.8 to 5.4×10 ¹⁹ cm^-3, respectively, was observed. Assuming dominant base recombination, the minority carrier lifetimes were also obtained from the current gains of the transistors which agree well with independent time-resolved photoluminescence values from from literature