Effect of Finger and Device-Width on Ruggedness of nLDMOS Device under Single-Pulse Unclamped Inductive Switching (UIS) Conditions

Abstract

This work demonstrates the effect of increasing finger number and width on the ruggedness of the nLDMOS device under test (DUT). The ruggedness or energy handling capability is analyzed by twodimensional (2-D) and three dimensional (3-D) device and circuit simulations. The set failure criterion in our study and simulation is the device temperature reaching a critical value equal to the melting point of metal-contacts. The maximum energy is calculated by considering the pass-case prior to device failure and time-integrating the drain voltage and current for the avalanche duration. Maximum avalanche energy handling capability is seen to be increased linearly with number of device fingers. UIS test was also performed on width extended multi-finger nLDMOS device structures. The simulated results provided useful approaches to predict real experimental results and contribute to their physical interpretation by identification of the mechanism of device-failure, hot-spot location and continuous temperature extraction.

Analysis of LDMOS for Effect of Fingers, Device-Width and Inductance (Load) on Reverse Recovery

“…For simulations we have taken two LDMOS device with a rated breakdown voltage of 67 V. Fig. 1(a) shows the UIS test circuit [5,6]. Fig.…”

“…This ruggedness is defined as the capability to withstand avalanche currents under unclamped inductive switching (UIS). Under UIS energy handling capability of Semiconductor device depends on number of fingers and device width [5].…”