Hot-carrier induced degradation mechanisms of 0.8μm LDD P-MOSFET with 850°C wet gate oxidation

Abstract

The hot-carrier induced degradation mechanisms of LDD p-MOSFET's have been investigated. Gate oxide layers were grown in a wet ambient at 850°C, which was reported as an advantageous candidate for a 0.8μm process. Degradation of the saturation drain current proceeds logarithmically in stress time while that of the linear current saturates. In addition to the trapping of electrons in gate oxide layers, donor-like interface states were generated by the hot carrier injection. The presence of the interface states was verified by measuring the degradation of the linear current and the threshold voltage after trapped electrons in the gate oxide are fully released. The interface state densities were estimated by fitting the calculated drain current degradation to the measured one by using two dimensional process and device simulators.