Spatial Distribution Analysis of Self-Heating Effect in High-Voltage MOSFETs

We have analyzed the self-heating effect in high-voltage (HV) MOSFETs, and have found that the self-heating effect first becomes larger with increasing gate-source voltage V_gs due to the current-density increase. However, it then starts to get smaller again with further increased V_gs. The reason is the spatial energy dissipation accompanied with the carrier injection into the resistive drift region. The effect is modeled and implemented into the circuit simulation model HiSIM-HV for HV-MOSFETs, and verified for real applications. It is shown that the magnitude of the self-heating effect on the drain current of HV-MOSFETs is not so drastic as normally expected. However, the self-heating which occurs in the drift region cannot be ignored, and must be considered as a thermal source for the electro/thermal simulation.