ANNEALING AND ELECTRICAL-PROPERTIES OF HG1-XCDXTE GROWN BY OMVPE

The annealing behavior of Hg(1-x)Cd(x)Te layers, grown by the conventional organometallic vapor phase epitaxy (OMVPE), is reported. Some of the as-grown layers, which are p-type with a concentration around 4 x 10(16) cm-3 of Group II vacancies, become light p-type with carrier concentrations around 1 x 10(15) cm-3 after Hg saturated annealings at temperatures in the range of 200-230-degrees-C. These conditions are typically expected to result in complete annealing and n-type conversion of the layer. These layers can be converted to n-type with a carrier concentration of approximately 5 x 10(14) cm-3 by a higher temperature anneal at 290-degrees-C, followed by a low temperature anneal at 220-degrees-C. Hall effect measurements were made under variable temperature as well as variable magnetic field conditions. Bulk carrier concentrations and mobilities were evaluated by considering the effect of the surface inversion/accumulation layer on the Hall data. It is proposed that p-type conduction in the partially annealed layers is due to the persistence of Group II vacancies in the Hg1-xCd(x)Te layers, which are not completely annihilated during the low temperature anneal. Conversion to n-type is probably due to residual donor impurities in the as grown Hg1-xCd(x)Te layer.