Characterization of LDMOS down to cryogenic temperatures and modeling with PSPHV

This article presents a detailed characterization and analysis of a 45 V LDMOS device from production technology across a wide temperature range from 33 to 385 K. For the first time, quasi-saturation behavior is consistently observed throughout the entire temperature range studied. Compared to prior published data, this device shows some notable differences, including a substantially higher saturation temperature of around 200 K for threshold voltage and subthreshold swing due to band tail and a typical low on-resistance down to 33 K, free of freezeout. To account for the observed temperature dependencies, we propose improved semi-empirical temperature scaling equations for the PSPHV model. We extend its applicable temperature range down to 33 K from the previous lower limit of 240 K. The enhancement models the temperature behaviors of key device parameters, including threshold voltage, subthreshold swing, mobility, velocity saturation, drift resistance, and quasi-saturation effects. These results provide new insights into the low-temperature behavior of LDMOS devices for cryogenic electronics applications.