Novel high voltage LDMOS on partial SOI with double-sided charge trenches

Abstract

A novel partial silicon-on-insulator (PSOI) high-voltage LDMOS is proposed and its breakdown mechanism is investigated numerically and experimentally. The PSOI LDMOS features double-sided charge trenches on the top and bottom interfaces of the buried oxide (BOX) (DTPSOI). In high-voltage blocking state, the charges located in the trenches enhance the electric field strength in the BOX, and a Si window makes the substrate share the vertical voltage drop and modulates the lateral field in the SOI layer. Both increase the blocking voltage (BV). A BV>700V DTPSOI LDMOS is realized on a 8μm-thick SOI layer over the 1.2μm BOX and 1.5μm-deep trench. Moreover, the Si window alleviates the self-heating effect.