A New Lateral NPN Transistor Structure for Power MOSFETs with On-Chip Protection

Power MOSFETs with built-in shorted load protection featuring a circuit based on a lateral npn transistor (LNPN) have been reported recently, however their performance can be limited by a parasitic vertical npn transistor (VNPN). In this paper a new LNPN structure is presented, which overcomes this problem. A dedicated implant has been introduced to optimize the performance of this new component. The results of the computer simulations are in good agreement with the experimental data. Power MOSFETs featuring the new component have been fabricated which are protected against load short circuit, overcurrents, ESD and overvoltages.