INSITU GROWTH SURFACE-TEMPERATURE MEASUREMENT FOR MOLECULAR-BEAM EPITAXIAL-GROWTH OF CDTE, ZNTE, AND CD1-XZNX TE ALLOYS

Direct measurements of the growth surface temperatures of (001) CdTe, ZnTe, and Cd1 xZnxTc (x = 0.1,0.25) epilayers were performed in situ by means of the condensation of Te2. Measurements were made over the technologically important 160–220 °C range for the molecular beam epitaxial growth of these materials. Condensation of Te2was observed when the incident flux of Te2exceeded the flux of Te2desorbing from the substrate as calculated at the temperature of the substrate. The surface temperature for the onset of condensation of an incident beam of Te2depends on the magnitude of the flux of the incident Te2molecules. The epilayer surface temperature was calculated by equating the expressions for the incident Te2flux and the desorbing Te2flux. Experimentally, the condensation of Te2was detected when transmission diffraction spots due to Te precipitates appeared, superimposed on the streaked reflection high-energy electron diffraction pattern of the substrate. The Te2condensation temperature measurements were reproducible to within 3 °C. The technique is accurate to better than 5 °C in absolute terms for measurements on (001) CdTe surfaces and 8°C for (001) ZnTe and Cd 1 xZnxTe surfaces. © 1990, American Vacuum Society. All rights reserved.