Silicon and indium doping of GaAs: Measurements of the effect of doping on mechanical behavior and relation with dislocation formation

Abstract The effect of indium and silicon doping on dislocation formation in GaAs single crystals has been studied experimentally using dynamic compression tests and indentation rosettes. By direct measurements of the critical resolved shear stress (CRSS) in temperature range from 400 to 1100° C using dynamic compression tests, we found that at the melting point, the critical resolved shear stress of GaAs: In is twice that of undoped GaAs. More recent measurements show that at high temperatures ( T ⩾ 1000° C) the critical resolved shear stress of silicon-doped crystals is lower than that of undoped GaAs. Well-defined indentation rosettes were obtained at high temperatures from a Vickers indenter using small loads. Analysis of such rosettes confirm that the mechanical behavior of the GaAs crystals is not drastically affected by the presence of dopants. Reduction of dislocation densities in doped crystals is attributed to modifications introduced by the dopant in the equilibrium concentration of native defects at the melting point (particularly gallium and arsenic vacancies).