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A Fourier transform far infrared spectrometer bas been constructed to perform reflectivity and transmission measurements on small semiconductor samples in the temperature range 10-300 grad. K. Far infrared and Raman spectra selection rules have been obtained by the Correlation method from the factor group analysis of the 5nS subset. Crystals of n- and p- type SnS bave been prepared, and the preparation methods are critically reviewed with reference to the T-p-x diagram. The electrical properties (Hall effect, carrier concentration, Hall mobility and barrier height) are measured for these specimens in the temperature range 40-3000 K. Methods of obtaining electrical contacts to SnS are exhaustively studied. Broadband photoconductivity and photovoltaic measurements are reported on n- and p-type specimens in the spectral range 0.5-2 .1 eV at temperatures from 300 grad. K to 10 grad. K. Band structure and impurity energies are suggested to account for the observed results. The band edge shift with temperature is also measured. Far infrared reflectivity and transmission measurements are made between 300 grad. K and 10 grad. K. in order to determine the lattice vibration frequencies. Kramers-Kroenig analysis and computer fitting routines are used to obtain this information from the reflectivity data. The interlayer forces are compared with those obtained in the isomorphic materials GeS and GeSe. Similar spectroscopic and analytic techniques have also been used to examine the room temperature optical properties of ZnS+Fe (Marmatite).

Power MOSFETs are often required to operate in a space radiation environment; therefore, they are susceptible to a catastrophic failure mode called single-event burnout. Single-event burnout of power MOSFETs is initiated by the passage of an energetic-heavy ion through the parasitic BJT inherent to the power-MOSFET structure. The electron-hole pairs generated by the ion support a short-lived current source which imposes a base-emitter voltage on the parasitic BJT. If a sufficient base-emitter voltage is imposed, the parasitic BJT enters second breakdown and burnout of the MOSFET occurs. A semi-analytical model has been developed to predict the energy required of the incident ion to initiate burnout. This thesis addresses the portion of this model which relates the energy of the incident ion to the base-emitter voltage imposed on the parasitic BJT. The initial base-emitter potential is determined using image-source techniques.

Electrical trim techniques for reducing the value of a trimmable single crystal silicon resistor (trimistor) are presented. Computer-controlled current pulses are used to incrementally decrease the value of the trimistor through metal/silicon alloying. Variations of both single and multipulse current pulses are investigated. Physical mechanisms, based on electron microscopy of trimistors trimmed under various conditions, are hypothesized to explain the observed trim behavior. Threshold currents are dependent on the initial value of the resistor, the applied current density and the trim method. The electrical trim technique for a single trimmable resistor element is optimized. The final resistance values of the trimmed trimistors are shown to be stable provided that a current at or above the threshold current is not applied thereafter. The performance of both N+ and P trim resistors is evaluated over temperature and accelerated operating life.