A novel LDMOS structure using P-trench for high performance applications

In this paper, we propose a new structure of silicon on insulator (SOI) lateral diffused metal oxide semiconductor (LDMOS) field effect transistors to improve the device performance. In the proposed structure, a trench is created in the buried oxide under the drift and drain regions and filled with p-type Si. We called the proposed structure as P-trench SOI-LDMOS (PT-LDMOS). Our simulations with two dimensional ATLAS simulator shows the unique features exhibited by the proposed structure in comparison with a conventional SOI-LDMOS (C-LDMOS). In the PT-LDMOS, the electric field is modified by producing a new additional peak at the electric field distribution, reducing the magnitude of electric field peak near the gate edge, removing of electric field crowding near the drift and drain junction at the bottom surface of the silicon layer, and making the surface electric field distribution more smooth. We optimize the doping concentration and the dimensions of the P-trench in the PT-LDMOS structure. Hence, the results illustrate the benefits of high performance PT-LDMOS over conventional one and expand the application of SOI-LDMOSs to high voltage.