Solid state reaction of thin metal films with mercury(1--x)cadmium(x)telluride

The solid state reactions of both e-beam evaporation and sputter deposition of thin layers of Cu, Co, and Ni onto CdTe and Hg{dollar}sb{lcub}0.8{rcub}{dollar}Cd{dollar}sb{lcub}0.2{rcub}{dollar}Te have been investigated using Transmission Electron Microscopy and Auger Electron Spectroscopy.; For a Cu overlayer deposited by either method on CdTe(111) and Hg{dollar}sb{lcub}0.8{rcub}{dollar}Cd{dollar}sb{lcub}0.2{rcub}{dollar}Te substrates, we observed formation of a relatively thick region of Cu{dollar}sb{lcub}rm 2-x{rcub}{dollar}Te (superlattice structure), even though the heat of reactions ({dollar}Delta{dollar}H{dollar}sb{lcub}rm R{rcub}{dollar}) are positive as calculated using bulk parameters.; Deposition of Co onto Hg{dollar}sb{lcub}0.8{rcub}{dollar}Cd{dollar}sb{lcub}0.2{rcub}{dollar}Te substrates reacted to form the {dollar}gamma{dollar}-phase (Co{dollar}sb3{dollar}Te{dollar}sb4{dollar}) at room temperature in the case of deposition by sputtering, and at 150{dollar}spcirc{dollar}C annealing temperature in the case of deposition by e-beam evaporation. This compound was stable at room and elevated temperatures (100{dollar}spcirc{dollar}C, 200{dollar}spcirc{dollar}C, 300{dollar}spcirc{dollar}C, and 400{dollar}spcirc{dollar}C). On the other hand Co did not react with CdTe (at temperature less than 300{dollar}spcirc{dollar}C) instead, generation of Te was observed. The Te generated in the case of sputter deposition and fast deposition (8-10A) e-beam evaporation was polycrystalline whereas, in the case of slow deposition (0.3-0.5A) e-beam evaporation it was amorphous. Auger depth profile indicated that the amount of excess Te in the case of sputter deposition was larger in compared with deposition by e-beam evaporation. The excess Te was distributed throughout the Co film.; The results of Ni deposited onto Hg{dollar}sb{lcub}0.8{rcub}{dollar}Cd{dollar}sb{lcub}0.2{rcub}{dollar}Te or CdTe substrate were somewhat similar to the Co cases. Ni reacted with Hg{dollar}sb{lcub}0.8{rcub}{dollar}Cd{dollar}sb{lcub}0.2{rcub}{dollar}Te at room temperature in either deposition system to form the {dollar}delta{dollar}-phase (NiTe-Ni{dollar}sb2{dollar}Te).; From the results of this work it is clear that the solid produced as a result of either e-beam or sputter deposition has a higher free energy than that of a metal layer on contact with the substrate. This result indicates importance of kinetics in the formation of the interface structure of metals deposited on Hg{dollar}sb{lcub}0.8{rcub}{dollar}Cd{dollar}sb{lcub}0.2{rcub}{dollar}Te substrates. (Abstract shortened with permission of author.)...