Proposal to Achieve the Ultimate Holding Voltage Tunability in Silicon Controlled Rectifiers (SCRs) for a Wide Range of ESD Protection Application

A novel silicon-controlled rectifier (SCR) concept for on chip ESD protection is proposed with holding voltage tunability from as low as 2V to the well breakdown voltage (10V). The novel proposal replaces the standard N+ and P+ implants in N-Tap/Cathode and P-Tap/Anode by P+-N+ implant and N+-P+ implants, respectively. Detailed physical insight of the proposed concept and several derivative concepts is given, explaining the trigger and holding voltage tunability. Besides, additional, rather refined, tunability is depicted by engineering the junction profile of the P+-N+ and N+-P+ implants. The proposed concept together with the junction profile engineering demonstrates the ultimate holding voltage tunability.