Terminal-optimized 700-V LDMOS with improved breakdown voltage and ESD robustness

A novel terminal-optimized triple RESURF LDMOS (TOTR-LDMOS) is proposed and verified in a 0.25-μ bipolar-CMOS-DMOS (BCD) process. By introducing a low concentration region to the terminal region, the surface electric field of the TOTR-LDMOS decreases, helping to improve the breakdown voltage (BV) and electrostatic discharge (ESD) robustness. Both traditional LDMOS and TOTR-LDMOS are fabricated and investigated by transmission line pulse (TLP) tests, direct current (DC) tests, and TCAD simulations. The results show that comparing with the traditional LDMOS, the BV of the TOTR-LDMOS increases from 755 V to 817 V without affecting the specific on-resistance (R_on,sp) of 6.99 Ω·mm². Meanwhile, the ESD robustness of the TOTR-LDMOS increases by 147%. The TOTR-LDMOS exhibits an excellent performance among the present 700-V LDMOS devices.