THERMAL-STABILITY OF PHOTOCHEMICAL NATIVE-OXIDE FILMS ON HG1-XCDXTE

Heat treatments were carried out on native oxide films grown on Hg1-xC dxTe by a photochemical process. The thermal stability of such layers was assessed by monitoring changes in depth profiles obtained from x-r ay photoelectron spectroscopy in conjunction with argon ion sputtering . After annealing, photochemical oxides grown in N2O showed a large ch ange in the oxide/Hg1-xCdxTe interface width and a movement of the Cd and Te interfaces towards the oxide surface. These results are compara ble to previous studies carried out on anodically grown oxides by othe r workers. For photochemical oxides grown in an O-2 ambient at slightl y higher temperatures, the oxide/Hg1-xCdxTe interface was observed to be very stable under the same annealing conditions, with no observable change in the oxide/Hg1-xCdxTe interface width and no movement of the individual element interfaces. For both the N2O and O-2 grown oxides, there was a significant loss of Hg from the oxide for extended anneal ing at 250 degrees C in a vacuum of 10(-5) Torr. (C) 1996 American Vac uum Society.