MOVPE growth of (100) CdZnTe layers using DiPZn

Abstract

Growth characteristics of (100) Cd1 − xZnxTe (CZT) have been studied in MOVPE. CZT layers were grown on (100) GaAs substrates using diisopropylzinc (DiPZn), dimethylcadmium (DMCd) and diethyltelluride (DETe) as precursors. Growths were carried out in the temperature range from 375 to 450°C. Since DiPZn has a lower vapor pressure than DMCd, CZT layers with a Zn composition below 0.06 were grown under good compositional controllability. Layers with uniform Zn composition and thickness over the growth surface were grown at this low Zn composition region. The crystallinity of the grown layers was also evaluated. The results showed that DiPZn is suitable for growth of CZT layers, wich lattice-match with the HgCdTe layers. Enhancement of the CZT growth rate was observed upon introduction of a small amount of DiPZn under fixed flows of DMCd and DETe. The Zn composition increases abruptly upon further increase of the DiPZn flow, where the growth rate decreases. Growth characteristics were also studied by changing the DiPZn ratio while keeping the sum of the DiPZn and DMCd flow rates constant. The growth mechanisms under the above growth conditions are also discussed.