NOVEL ESD PROTECTION TRANSISTOR INCLUDING SIGE BURIED LAYER TO REDUCELOCAL TEMPERATURE OVERHEATING

This paper introduces a new NMOS electrostatic discharge (ESD) protect ion transistor which contains a buried SiGe narrow-bandgap layer betwe en the source and the drain region. The simulations carried out by a t wo-dimensional simulator show that the ESD induced current flows mainl y through the buried layer in the new structure, which strongly suppre sses local overheating on the silicon surface. As a result, the peak l attice temperature for the Machine Model with 300 V level is 400 degre es C in the new structure, which is much lower than in the normal stru cture, 1150 degrees C. In the new structure, the parasitic bipolar tur n-on is faster and the bipolar current gain (beta) is higher than in t he normal structure by as much as 8 ns and 10 times, respectively. The snapback voltage is reduced by 1.5 V in the new structure.