UBC Theses and Dissertations
Studies on gallium arsenide technology Boyd, Graeme B.
Before gallium arsenide technology can mature, a suitable dielectric layer is required. In previous work several dielectrics have been tried, ranging from thermally grown native oxide to anodically oxidized aluminium, but as yet no suitable dielectric has been found. In the present work two dielectric layers were investigated for their suitablity, these being anodic native oxide and anodic zirconium oxide. Optical and electrical properties of both oxides were used as the testing methods for the investigation. The electrical properties were deduced from examining capacitance-voltage and conductance-voltage characteristics. The optical properties were observed using an ellipsometer. The wavelength of light used in the ellipsometer was 632.8 nm. Several ↓-Δ points were obtained for each sample by changing the angle of incidence so that the optical indices and film thickness could be found. The optical and electrical properties of the anodic native oxide were found to be similar to those previously reported. The anodic zirconium oxide optical and electrical properties were found to be extremely dependent upon the annealing history. In one case after annealing, the optical indices could no longer be determined while in another case the indices remained unchanged but the thickness decreased and surface "bumps" were detected. It was also found that after annealing, the oxide was excessively leaky. Before a full understanding of these effects can be obtained, further work is required.
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