N-TYPE AND P-TYPE DOPANT PROFILES IN DISTRIBUTED BRAGG REFLECTOR STRUCTURES AND THEIR EFFECT ON RESISTANCE

We report the n- and p-type dopant profiles obtained in AlAs/GaAs structures. When structures were doped with Si or C, targeted dopant profiles were achieved. However, when Be was used, significant redistribution of the dopant occurred, which resulted in an accumulation of Be on the GaAs side of the heterointerfaces, and a maximum incorporation of Be of approximately 5 X 10(-17) cm-3 in the AlAs layers. Similar results were obtained for Be dopant profiles in AlGaAs/AlAs quarter-wave distributed Bragg reflectors (DBR). Be segregation and diffusion during growth resulted in a high electrical resistance in these DBR structures. The resistance was significantly reduced when the structure was doped with C.