Electrical and Computer Engineering ETDs

Publication Date

Spring 5-9-1972


GaAsP MIS capacitors were fabricated using several dielectric-growth processes, including RF sputtering, wet oxidation, and dry oxidation of GaAsP. Dry oxidation of GaAsP surfaces produced MIS devices having the best charac­teristics. Instabilities of early MIS capacitors were over­come by use of thermal cycling techniques and chromium-doped dielectrics. Deep-depletion characteristics were observed for GaAsP MIS C-V curves, even in the range of applied bias which theoretically should result in inversion of the GaAsP surface. Both low-frequency and high-frequency C-V data support the conclusion that inversion characteristics were not observed for GaAsP MIS capacitors. Calculated high-frequency surface-state density and surface-state charge values of Nss=1.6 x 1010 states/cm2 and Qss=-2.55 x 10-9 coulombs/cm2 were obtained.

Data from electron-radiation experiments correlated very well with gamma-radiation experimental data. Flat-band voltage shifts were less than 2.5 volts for total ionizing doses up to 106 rads (GaAsP).

Depletion capacitance theory was used to calculate the neutron-induced carrier removal rate in GaAsP MIS capacitors. At a neutron fluence of 1014 n/cm2, the carrier removal rate was determined to be -Δn/ΔΦn = 22 cm-1.

Annealing experiments were performed to determine whether "permanent" radiation damage could be annealed out of the GaAsP MIS capacitors. Good results were obtained by passively annealing the devices for 1 hour at 150 ° C. How­ever, annealing at higher temperatures (325° C) was found to have deleterious effects on the capacitors. Similar results were obtained for electron, gamma, and neutron-irradiated capacitors for radiation levels up to 106 rads(GaAsP) and 1015 n/cm2.

Radiation testing of GaAsP MIS capacitors and GaAsP diodes resulted in the development of a magnetic electron deflection tube, a telescoping drift tube, an electron-beam TREE test fixture, and a radiation-hardened line-driver amplifier.

Document Type


Level of Degree


Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Wayne Willis Grannemann

Second Committee Member

Ahmed Erteza

Third Committee Member

Harold Dean Southward