Design of a novel triple reduced surface field LDMOS with partial linear variable doping n-type top layer

Abstract A novel triple reduced surface field (RESURF) lateral double-diffused metal oxide semiconductor field effect transistor (LDMOS) with partial linear variable doping (LVD) N-type top (N-top) layer is proposed in this paper. Compared with the conventional triple RESURF LDMOS, a partial LVD N-top layer is introduced in the surface of N-well, providing a low on-resistance conduction path and leading to an optimized surface electric field, which alleviates the inherent tradeoff between the breakdown voltage (BV) and specific on-resistance ( R on , sp ). With the n-drift region length of 70 μm, the novel triple RESURF LDMOS obtains a high BV of 847 V and a low R on , sp of 79 mΩ cm 2 which are 76 V higher and 46 mΩ cm 2 lower than those of the conventional triple RESURF LDMOS. Therefore, the novel triple RESURF LDMOS can greatly improve the tradeoff between BV and R on , sp . Furthermore, compared with the other existing technologies in the high BV level, the novel triple RESURF LDMOS can achieve a highest figure of merit (FOM, defined as BV 2 / R on , sp ) of 9.08 MW/cm 2 and the conventional RESURF silicon limits are broken.