GaAs APD's and the effect of rapid thermal annealing on crystalline quality of GaAs grown on Si by MBE.

Photoluminescence, Rutherford back-scattering/channeling, x- ray double crystal rocking curves, and minority carrier lifetime suggest that structural and optical properties of GaAs grown on Si by MBE improve greatly as a result of post growth rapid thermal annealing (RTA). Transmission electron microscopy, in contrast, shows no significant reduction in defect density (~10 sup 8 cm sup (-2)) after RTA although defect configuration is affected. Dislocations tend to organize better and combine each other after RTA. The minority carrier (electron) lifetime was measured at 2 ns and 2.7 ns with and without RTA in p sup + GaAs(p > 10 sup (18) cm sup (-3)). Annealing at a temperature as low as 750C and of a layer as thin as 0.1micron also produces a significant improvement in PL intensity. It is suggested that in-situ RTA after a short growth (~0.1 micron) followed by the growth of rest of the structure may result in substantial improvement in material quality.