Comparison of MOSFET Threshold Voltage Extraction Methods with Temperature Variation

Threshold voltage is a fundamental parameter for MOSFET device and technology characterization. Multiple threshold voltage extraction methods are compared in this paper with experimental data over a wide temperature range from -40°C to 150°C for 5V and 1.8V NMOS devices in a 180 nm BCD process. Consistent results are found among two linear extrapolation methods from the drain current versus gate voltage transfer characteristics and transition method for MOSFETs biased in the linear region. The difference in temperature coefficients of extracted threshold voltages from different methods are compared and the different trends of scaled drain currents at extracted threshold voltages over temperature are analyzed to reveal the underestimation of threshold voltage temperature coefficients in gm/Id methods.