Influence of the growth condtions on the incorporation of deep levels in VPE GaAs

Vapor‐phase epitaxial (VE) n‐type GaAs layers have been grown through the classical Ga/AsCl3h2 method unde different growth conditions. The AsCkl3 mole fraction X and the source and deposition temperatures have been changed separately. The variation of the growth rate τ of the layers versus X shows that two growth regimes occur: for small values of X, τ increases with X, while it decreases at highe values. This clearly demonstrates that the growth is limited by kinetic effects. In both regimes, for undoped materials, the residual free‐carrier concentration nT* is very sensitive to the growth parametes. In undoped layers, nnT* varies like the growth rate in the first growth regime, i.e., for small X. For the highest values of X, NT* decreases like n:NT* appears to be proportional to ND, i.e., to SiGa. Intentional doping of the layers with sulphur leads to an increase of nT*. Again, NT* is proportional to the sulphur concentration. The origin of the involved defect is discussed. According to these experimen...