TCAD simulation of hot-carrier stress degradation in split-gate n-channel STI-LDMOS transistors

Abstract

A combined experimental and simulation analysis of the degradation mechanisms induced by hot carriers in a silicon-based split-gate n-channel LDMOS transistor featuring an STI structure is reported. In this regime, electrons can gain sufficient kinetic energy necessary to create charged traps at the silicon/oxide interface, thus inducing device degradation and causing the shift of the electrical parameters of the device. In particular, the on-resistance degradation in linear regime has been experimentally characterized at different stress conditions and at room temperature. The hot-carrier degradation has been reproduced in the frame of TCAD simulations by using physical-based models aimed at reproducing the degradation kinetics. An investigation of the electron distribution function at different stress conditions and its dependence on the split-gate bias is carried out achieving a quantitative understanding of the role played by hot electrons in the hot-carrier degradation mechanisms of the device under test.