Substrate quality impact on the carrier concentration of undoped annealed HgCdTe LPE layers

The impact of Te precipitates and impurities, in CdZnTe or CdTe substrates, on grown liquid phase epitaxy (LPE) HgCdTe layer hole concentrations was s tudied. The carrier concentrations in capped annealed LPE HgCdTe layers gro wn on CdZnTe substrates with large densities of Te precipitates are frequen tly significantly higher than those expected for HgCdTe annealed under Hg-d eficient conditions. The carrier concentration in the LPE layer, due to the diffusion of copper ions from contaminated CdTe substrates into the layer, is strongly affected by the polarity of the (111)-oriented substrates. Lay ers grown on the (111)A face showed very high concentrations of Cu, whereas in those grown on the (111)B face normal carrier concentrations were achie ved. These phenomena are discussed on the basis of defects formed either in the epilayer or in the layer-substrate interface.