EXCIMER-LASER SPUTTERING DEPOSITION OF TIO2 OPTICAL COATING FOR SOLAR-CELLS

We have investigated the ArF laser sputtering deposition of TiO2 anti- reflection coatings, aiming at large scale production of II-VI and III -V solar cells, the main theme of our research group. As a first step, layers were deposited on silicon wafers and glass. A reasonable growt h rate for production, considering possible pulse frequencies of a few tens Hertz, of 0.1 Angstrom per 1 J/cm(-2) laser pulse energy density was obtained. The structure of the oxide layer, interface and interdi ffusion with the substrate are characterized using cross sectional hig h resolution transmission electron microscopy and Rutherford backscatt ering, as a function of substrate temperature on the one hand and argo n, nitrogen and oxygen pressure during deposition on the other hand. T he surface optical quality of the deposited films versus thickness and growth conditions is presented. We will apply this technique to a sol ar cell prototype and a GaSb based photodetector prototype fabricated in our group.