An S-type folded channel LDMOS for decreased specific on-resistance <i>R</i> _on-sp

Abstract An S-type folded channel (SFC) lateral double-diffused metal-oxide-semiconductor (LDMOS) with reduced specific on-resistance is proposed, and its physical mechanism is studied by SENTAURUS. Its channel is folded into a structure with a shape similar to an ‘S’. In the on-state, the inversion layer of the conductive channel exhibits an S-folded shape, which expands the width of the channel and enhances the electron injection capability, reducing the specific on-resistance ( R on,sp ). In this paper SFC LDMOSs are prepared by different processes: SFC LDMOS1 is prepared by the traditional preparation method while SFC LDMOS2 is ion-implanted with another thin and highly doped N+ drift region in the P-well region, which can better optimize the electric field distribution and increase the doping concentration in the drift region, thus further reducing R on,sp . Three-dimensional simulation results show that the breakdown voltage and R on,sp are 162 V and 3.98 mΩ cm 2 , respectively, and the Baliga figure of merit (FOM) reaches 6.60 MW cm −2 . Compared with the conventional LDMOS, the R on,sp value of SFC LDMOS2 has been reduced by 33.3% and the FOM increased by 65%, which breaks the reduced surface field (RESURF) silicon limit.