S-Doped GaInAs Grown By Chemical Beam Epitaxy: Electrical And Structural Characterization

Abstract

AbstractWe report on the electrical and structural characterization of sulfur (S) doped Ga0.73In0.27As layers, grown on SI (001) GaAs substrates by chemical beam epitaxy. The room temperature free electron concentration is 2×1017cm−3 while the corresponding value of mobility is 3400 cm2V−1 s−1. The epilayer is characterized by a deep trap, which could be attributed to the electrical activity of dislocations, with an activation energy of 0.59 eV and a capture cross section 6×10−15 cm2. TEM analysis shows that the GaInAs/GaAs interface is characterized by dislocation lines and loop-like configurations which could be attributed to climb movement by point defect absorption or emission. Annealing at 420°C (Ar ambient for 5 min) does not alter the carrier concentration (n) and mobility (μ) significantly. The invariance of n and μ, even though the temperature should be high enough to dissociate any Satomic hydrogen complexes, indicates that the number of hydrogen-S donor complexes in the as-grown material is small compared with the donor concentration. Finally, the effect of intentional atomic hydrogen diffusion is discussed.