New experimental observations on the electrical characteristics of the Al/SRO/Si diode, and annealing effects

The electrical characteristics of the Al/Silicon Rich Oxide (SRO)/Si device are studied as a function of bulk concentration of N and P type silicon wa fers, and different contents of excess silicon and thickness of the SRO fil m. It is experimentally observed that depending on the type and impurity co ncentration of the silicon substrate, the I-V relationship can have a high current regime for positive and negative polarities, and also that the curr ent can saturate for the polarity that produces Si surface inversion. These experimental observations are explained as a result of the electron hole p air generation in the depleted region, and also due to further increase of the width of this region. It is shown that the onset electrical field (E-on ) is lightly influenced by annealing at high temperature. This variation is more evident as the excess silicon increases, and this effect can be assoc iated to the structural change that high temperature annealing produces on the SRO. A simple method to estimate the excess silicon is also proposed. ( C) 1999 Elsevier Science Ltd. All rights reserved.