In this talk, the deposition of dense arrays of CdTe/CdS photodiodes, via close-spaced sublimation, is presented for the first time. The previously reported ordered polycrystalline method was used to fabricate the photodiode arrays with the feature size ranging from 1 to 2 micrometers on a pitch of 2 to 4 microns, respectively. Reactor conditions that yielded selective-area deposition and greatly reduced deposition rates of CdTe were developed and optimized to increase the grain size and concomitantly reduce the number of CdTe nuclei within each photodiode. The effects of grain size on electrical characteristics are presented. The growth evolution and selectivity were studied using scanning electron microscopy, atomic force microscopy and x-ray diffraction. A model that describes the selective-area deposition of CdTe via close-spaced sublimation is presented. The experimental results and model are general and could be applied to other polycrystalline film materials.
Arev Escobedo is in his second year in the Electrical Engineering master’s program. As part of his master’s studies, Arev will be doing an internship at Texas Instruments in 2007. He received his bachelor’s degree at UTEP in Dec. 2005. He is a native of the cities of El Paso/Ciudad Juarez.