RADIATION EFFECTS IN THIN FILM TRANSISTORS.
Abstract
The purpose of the present investigation was to improve the performance of the silicon-on-sapphire thin film transistor in a high energy radiation environment. This is to be accomplished by a study of the influence of various design variables, selected on the basis of design theory and previous work, on the device performance in this environment. The investigation consisted of radiation effects testing of specially fabricated devices with known design variations, and interpretation of the experimental data on the basis of the principles of analysis of variance. The development of design equations was carried out and compared with the experiment. The test devices were exposed to pulsed bremsstrahlung, the combined gamma and neutron environment of the pulsed nuclear reactor, and to the gamma radiation of a Co60 source. Under pulsed bremsstrahlung irradiation, the thin-film-device response, as measured by the transient drain current, was one-fifth that of a bulk device of the same geometry. For the statistically designed experiment, the factors chosen were the gate insulator thickness, channel geometry, and silicon resistivity. For the threshold voltage shift all factors were significant above the 0.05 significance level. The preferred design, defined by the smallest negative shift in threshold voltage, is correlated with lower resistivity, larger oxide thickness, larger channel width, and shorter channel length. A theory for the dependence of threshold voltage shift as a function of time was developed and shown to give good agreement with experiment. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1968
- Accession Number
- AD0824931
Entities
People
- Cedric C. Berggren
- David A. Horowitz
- Vincent R. Honnold
- Willard M. Peffley
Organizations
- Hughes Aircraft Company