Self-Heating Characterization and Extraction Method for Thermal Resistance and Capacitance in High Voltage MOSFETs

摘要

This work reports on the self-heating effect (SHE) characterization of HV DMOSFETs and the accurate extraction of the equivalent thermal impedance of the device (thermal resistance, R_(TH), and capacitance, CTH) needed for advanced device and IC simulation. A simple pulsed-gate experiment is proposed and the influence of its parameters (pulse duration and duty factor) are analysed. It is demonstrated that in our 100V DMOSFET, SHE is cancelled by using pulses with duration less that 2μs and duty factor lower that 1:100. The new extraction method of device thermal resistance and capacitance exploits analytical modelling and dedicated extraction plots using the measurements of output characteristics at various applied pulses and the gradual reduction of SHE with pulse duration and duty factor. Both R_(TH) and C_(TH) are assumed and extracted in saturation region as quasi-independent functions of the device bias (injected power) at a given external temperature. We originally report on the temperature dependence of the HV device thermal resistance that is shown to be a linear function of external temperature (in our device, R_(TH) could increase by almost 100% over 100℃). SPICE simulations with the extracted thermal R_(TH)-C_(TH) circuit are finally used to fully validate the proposed method.