Analysis of Heat Generation from a Power Si MOSFET

This paper describes the thermal properties of power Si MOSFETs. Recently, the thermal problems of driving devices have been gaining attention. The thermal design of semiconductor chips is important since the main heat source in a driving device is the semiconductor chips. Power Si MOSFETs, which are widely used as semiconductor devices in car electronics, have serious thermal problems, since they use high voltages. Therefore, the thermal properties of power Si MOSFETs must be studied in order to improve the reliability of the electronics. In this study, the thermal properties of power Si MOSFETs are discussed. To investigate these thermal properties, calculations are performed using electrothermal analysis. From the calculations, a hot spot appears in the power Si MOSFET, and the hot spot temperature rises with increase in the applied voltage. Furthermore, the difference between the hot spot temperature and the average temperature becomes greater with the increase in applied voltage. The results indicate the risk of conventional thermal design with the assumption of uniform heat generation.