The multiple-trapping model and hole transport in SiO2

Abstract

An understanding of the charge‐transport process in SiO₂ is vital to an understanding of radiation effects in MOS devices. To account for hole transport in SiO₂ below room temperature, a stochastic hopping transport model has been employed by others with considerable success. An alternate model is presented here which explains many experimental data in an even more satisfactory fashion. This model is based on multiple trapping at a continuum of trapping levels, the concentrations of which decrease exponentially with energy from the valence band edge. By adjusting the parameters of the model to fit the data at a single temperature, behavior at other temperatures for the same specimen is accurately predicted, including the variation of apparent activation energy with the amount of transport that has occurred. This feature and others which are discussed are not shared by the hopping model previously employed.