Abstract

We have investigated the ArF laser sputtering deposition of several materials, in cluding TiO₂ and MgO, for antireflection coating, aiming at large scale production of II-VI and III-V solar cells, the main theme of our research group. Layers were deposited on several semiconductor materials used for solar cells and photodetectors: Si wafers and glass on a first step, followed by GaAs and GaSb substrates. A reasonable growth rate for production was obtained, considering possible pulse frequencies of a few tens of Hertz (0.1 A per 1 J/cm⁻² laser energy density per pulse). The structure of the thin films fabricated, as well as diffusion at the interface with the substrate, is investigated using cross-sectional high-resolution transmission electron microscopy, when substrate temperature, nitrogen, and oxygen partial pressure in the atmosphere of the chamber are changed during deposition. The surface optical quality of the deposited films vs thickness and growth conditions is presented, and roughness was measured with a stylus profiler. We have applied this technique to a solar cell prototype and a GaSb based photodetector prototype fabricated in our group.

© 1994 IEEE