Novel Silicon-Controlled Rectifier With Snapback-Free Performance for High-Voltage and Robust ESD Protection

A novel snapback-free silicon-controlled rectifier (SFSCR) with P-type Zener implantation (ZP) is developed in a 0.5-mu m bipolar CMOS DMOS technology for latch-up immune high-voltage (HV) electrostatic discharge (ESD) protection. The inherent snapback of SCR is successfully suppressed by the novel ZP technique. But, it also brings about a serious degradation in failure current (I-t2) when compared with the regular low holding voltage (V-h) device. In order to mitigate such degradation, a novel layout terminal is proposed. According to the transmission-line pulse test results, I-t2 of the SFSCR with new layout is increased by 58.5%, while the ON-state resistance (R-ON) is reduced by 48.7% under the same layout area. By comprehensive comparison, the SFSCR is proved to be a potential HV ESD solution.