Multiwafer growth of CdTe on GaAs by metalorganic chemical vapor deposition in a vertical, high-speed, rotating disk reactor

Abstract

Growth of CdTe (111) layers on GaAs (100) and GaAs (111) substrates by metalorganic chemical vapor deposition (MOCVD) has been investigated using a commercial, vertical, high-speed, rotating disk reactor. Dimethylcadmium (DMCd) and diisopropyltelluride (DIPTe) were used as the growth precursors. The growth rate was measured over the temperature range from 308 to 402 °C. DMCd molar growth efficiencies greater than 50% are obtained for growth temperatures greater than 368 °C. X-ray rocking curves for the (422) and (333) reflection planes of CdTe (111)<90 arcsec full width at half maximum were obtained at 380 °C for films on the (111) substrates. Scanning electron microscopy on cleaved wafers and infrared interference spectroscopy show edge-to-edge thickness uniformity to be 1.3%. The far-infrared reflectivity was measured using a Fourier transform infrared spectrometer to obtain the TO phonon spectra. These data indicate that the thickness and dielectric constant of the CdTe is extremely uniform. Overall, the films obtained in this study are more uniform and of higher quality than the best films produced in a horizontal reactor using similar growth procedures.