Optical and electrical studies of interface traps in the Si/SiO2 system by modified junction space-charge techniques

Document Type

Article

Publication Date

1-1-1989

Abstract

Interface traps in the Si/SiO2 system have been examined by adapted-junction space-charge methods. Principal photoionization thresholds, observed at 86 K, are Ev+0.38 eV for excitation of holes from traps, and Ec-0.35 eV and Ec-0.8 eV for electrons. These are assigned to the two levels of the Pb center. The photoionization thresholds differ by 0.050.1 eV from Pb levels at Ev+0.3 eV and Ec-0.3 eV, as previously observed by capacitance-voltage (C-V) analysis, deep-level transient spectroscopy, and gated electron-spin resonance (ESR). This suggests a configuration change with electron occupancy, in accord with molecular-orbital calculations. Single-shot measurements of thermal emission rates for holes and electrons in the range 150185 K show activation energies from 0.29 to 0.36 eV, which are corroborated by deep-level transient spectroscopy. Pulse-train measurements show that capture rates do not exhibit a pronounced temperature dependence. Exponential capacitance transients from emission and capture measurements are discussed with respect to previous C-V and ESR studies which suggested wider Pb levels. © 1989 The American Physical Society.

Publication Title

Physical Review B

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