Growth of Arsenic-Doped Hg1– xCdxTe (x ~ 0.4) Epilayers by Metalorganic Chemical Vapor Deposition

Abstract

We have studied arsenic incorporation from tris(dimethylamino)arsine into epitaxial Hg_{1– x}Cd_xTe (x ~ 0.4) layers grown by the metalorganic chemical vapor deposition interdiffused multilayer process (MOCVD-IMP) on GaAs (310), (100), and (111)B substrates. CdTe was grown from dimethylcadmium and diethyltellurium vapors, and HgTe, from diisopropyltellurium and mercury vapors. Arsenic incorporation into the layers has been shown to depend on the crystallographic orientation of their growth, increasing in the order (111)B < (100) < (310). The addition of tris(dimethylamino)arsine during CdTe sublayer growth in an excess of diethyltellurium has been shown to have no significant effect on the macroscopic composition of the HgCdTe layers. The arsenic-doped HgCdTe layers have p-type conductivity. The fraction of electrically active arsenic in the layers depends on its concentration and rises from 15 to 85% in going from the (111)B to (100) and to (310) orientation. Additional two-step annealing ensures a near 100% arsenic activation in the HgCdTe layers.