A New Conductivity Modulated LDMOSFET Employing Buried P Region and P+ Drain

We have proposed and fabricated a new lateral double diffused metal–oxide–semiconductor field effect transistor (LDMOSFET) entitled conductivity modulated (CM)-LDMOSFET which increases the saturation current and decreases the on-state voltage drop. The current capability of the proposed device was improved due to conductivity modulation by employing a buried p region and a p+ drain junction. Experimental results showed that the on-state voltage drop of the CM-LDMOSFET was lower than that of the conventional LDMOSFET when the current density was higher than 200 A/cm2 and the saturation current of the CM-LDMOSFET at the gate voltage of 15 V was 50% greater than that of the conventional LDMOSFET. The fabrication process of the CM-LDMOSFET is not complicated and is compatible with the conventional LDMOSFET and lateral insulated gated bipolar transistor (LIGBT) processes.