Application of multi-lateral double diffused field ring in ultrahigh-voltage device MOS transistor design

Abstract

A novel ultrahigh-voltage device with multi-lateral double diffused field ring in reduced surface field (RESURF) lateral double-diffused MOS (LDMOS) transistor in junction-isolated power IC technology is developed and successfully simulated. The multiple rings of P+ implant used linearly p-top mask design to form multi-lateral diffused field ring to cause many depletion regions. Due to charge balance effect, the multiple p-top rings makes the doping concentration of the N-drift region increased to cause the specific on-resistance reduced. The proposed multiple p-top rings RESURF LDMOS device is able to achieve a specific on-resistance of lower than 144.7 mΩcm2 while maintaining a breakdown voltage of over 800 volts.