Self Heating Characterization of 32V MOSFETs using Pulsed Gate Measurement

High voltage (HV) MOSFETs are extremely interesting for automotive, medical ultra-sound, flat panel LCD displays, RF and many other applications. One of the key phenomena related to the operation of HV devices is the self heating effect (SHE). Intuitively SHE represents the heating of the device due to its internal power dissipation. SHE results in a reduction of the drain current and the negative output conductance effect. In this work we measure the self heating effect of 32 V MOSFETs fabricated in Silterra\´s 180 nm HV CMOS process technology. We extract the equivalent thermal impedance of the device (thermal resistance, R_TH and capacitance, C_TH). These parameters are needed for circuit simulation for circuit design. A pulsed gate measurement is used in order to be able to measure the device characteristics when it is still "cold." The pulse width is typically 2 mus. The influence of pulse duration is analyzed.