Increasing substrate resistance to improve the turn-on uniformity of a high-voltage multi-finger GG-nLDMOS

摘要

With the impact of the non-uniform turn-on phenomenon, the ESD robustness of high-voltage multi-finger devices is limited. This paper describes the operational mechanism of a GG-nLDMOS device under ESD stress conditions and analyzes the reason that causes the non-uniform turn-on characteristics of a multi-finger GG-nLDMOS device. By means of increasing substrate resistance, an optimized device structure is proposed to improve the turn-on uniformity of a high-voltage multi-finger GG-nLDMOS. This approach has been successfully verified in a 0.35 μm 40 V BCD process. The TLP test results reveal that increasing the substrate resistance can effectively enhance the turn-on uniformity of the 40 V multi-finger GG-nLDMOS device and improve its ESD robustness.