Record Details
Vacuum evaporated dielectrics in MOS structures
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Vacuum evaporated dielectrics in MOS structures |
| Names |
Delzer, Dennis Richard
(creator) Looney, James C. (advisor) |
| Date Issued | 1968-08-27 (iso8601) |
| Note | Graduation date: 1969 |
| Abstract | Vacuum evaporated dielectrics for use in MOS structures were studied in this research project. Dielectric films were deposited on substrates by electron bombardment evaporation of sapphire and quartz source materials. These deposited films were studied using infrared spectroscopy, index of refraction, density, and dielectric constant measurements. Etching tests were also conducted on the dielectric films. Annealing these films was also tried. From the results of these tests, it was concluded that suitable aluminum oxide and silicon dioxide films can be obtained by e-Gun evaporation. The best results were obtained for slowly evaporated films on substrates heated above 200° C. Better films were obtained after annealing for ten minutes at 1100°C in dry nitrogen. The diffusion masking properties of the e-Gun evaporated silicon dioxide and aluminum oxide films were studied. The evaporated films were tested for the masking of phosphorus and boron diffusion into silicon, of gallium and indium diffusion into germanium, and of zinc diffusion into gallium arsenide. From the results of these tests, it was concluded that both of these e-Gun evaporated films will effectively mask the diffusion of all the above mentioned impurities. The aluminum oxide films were better diffusion masks because they were more impervious to the diffusion of impurities. It required significantly thinner films of aluminum oxide to effectively mask the diffusion of all the impurities studied. The e-Gun evaporated films were used to fabricate MOS capacitors. Both aluminum oxide and silicon dioxide films produced good capacitors. The threshold voltages and surface-state densities of the capacitors were studied. Aluminum oxide films produced MOS capacitors which were relatively stable under bias-temperature tests. The e-Gun evaporated films were used in the fabrication of MOS transistors. The electrical properties of these transistors were studied using I-V characteristics. Both dielectrics produced good MOS transistors. Aluminum oxide films produced transistors with transconductances which were twice as large as the transconductances of the transistors with silicon dioxide films of the same thickness. The aluminum oxide films produced transistors which were relatively stable under bias-temperature tests, a possible reason for this being that impurity ions are less mobile in it than in silicon dioxide. |
| Genre | Thesis/Dissertation |
| Topic | Transistors |
| Identifier | http://hdl.handle.net/1957/46875 |
