Study on Zn Diffusion in GaAs and AlxGa1-xAs (x≤0.4) at Temperatures from 726° to 566°C

Zn diffusion in GaAs and Al x Ga 1- x As ( x ≤0.4) was investigated at temperatures from 566° to 726°C, with 5/50/45 (Ga/As/Zn) and ZnAs 2 sources. The time and temperature dependence of the diffusion depth in GaAs was obtained as d (µm)=4.55×10 6 √ t (h)exp (-1.20 e V / k T (K)) for a wide temperature range (566°–950°C). The activation energy E c obtained from the temperature dependence of Zn concentration in the diffused layer was found to be 0.68 eV which agreed with calculations based on thermochemical analysis taking Ga self-diffusion into consideration. It was observed that X j = d /√t in Al x Ga 1- x As monotonically increased with increasing x and that the activation energy of X j for Al 0.3 Ga 0.7 As was 1.03 eV which was smaller than that of 1.20 eV in GaAs. The present results for Al x Ga 1- x As are explained by considering the increase in the lattice binding energy with Al content x , based on an I-S diffusion model of Zn.