Negative bias instability at the SIMOX buried oxide-silicon overlayer interface

Abstract

A study is made of negative bias instability associated with the buried oxide - silicon overlayer interface. Generated positive charge levels are measured from the shift in MOSFET transfer characteristics and interface state generation by charge pumping. The conclusion is that the same mechanism believed to account for NBI in thermal oxides can explain the instability seen in SIMOX oxide. The work has relevance for the long term stability of SOI based circuits which are likely to be particularly prone to NBI due to the device self heating which will thermally activate the instability.