Carrier Recombination and Trapping in Heteroepitaxial Si/Spinel

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Abstract
Measurements of transient conductance in response to 80‐nsec pulses of 4–20‐keV electron irradiation have been used to investigate electrical properties of defects in 2–4‐μ Si films on 〈111〉 MgO·Al2O3 spinel. Carrier lifetimes ∼ (2–3) × 10−10 sec are estimated from the conductance change during irradiation. Significant trapping of injected carriers is indicated by the postirradiation conductance decay, which persists beyond 10−5 sec at 300°K and 10−3 sec at 90°K. The time and temperature characteristics of the decay suggest that ionized defects equilibrate by carrier capture over a potential barrier as in neutron‐irradiated silicon. Variable‐energy electron irradiation was used to investigate the depth dependence of defect density, and the results indicate that trapping in Si/spinel is greater near the substrate inferface.