Measurements of transient conductance in response to 80hyphen;nsec pulses of 4ndash;20hyphen;keV electron irradiation have been used to investigate electrical properties of defects in 2ndash;4hyphen;mgr; Si films on lang;111rang; MgOmiddot;Al2O3spinel. Carrier lifetimes sim; (2ndash;3) times; 10minus;10sec are estimated from the conductance change during irradiation. Significant trapping of injected carriers is indicated by the postirradiation conductance decay, which persists beyond 10minus;5sec at 300deg;K and 10minus;3sec at 90deg;K. The time and temperature characteristics of the decay suggest that ionized defects equilibrate by carrier capture over a potential barrier as in neutronhyphen;irradiated silicon. Variablehyphen;energy electron irradiation was used to investigate the depth dependence of defect density, and the results indicate that trapping in Sisol;spinel is greater near the substrate inferface.
展开▼
