State of the Art 40V-100V n-channel LDMOS Design on Thin Box SOI with High Energy Capability

The design concept of a state of the art 40V to 100V n-channel LDMOS is described in this paper. With aggressively thinner buried oxide (BOX) layer, for the first time, a SOI based power LDMOS has achieved comparable energy capability as Bulk BCD technology.

The main reason for this excellent performance in Thin BOX SOI turned out to be the better thermal conductivity of the lowly-doped SOI handle wafer which outruns the CMOS highly doped p+ bulk substrate. With proper top silicon thickness consideration, a wider voltage range of LDMOS family is constructed. For 40V POWER MOSFET, 57V/23mΩ.mm2 is obtained, one of the best values reported so far.