New Bidirectional Silicon-Controlled Rectifier for Low-Voltage ESD Protection

Electrostatic discharge (ESD) protection is an important issue for the modern integrated circuits (ICs). As for the input/output (I/O) pins having a varying operating voltage in the positive and negative ranges, the traditional diode or GGNMOS architecture is not applicable, making the corresponding ESD design more difficult. Among the several widely used ESD protection devices, the silicon-controlled rectifier (SCR) has a high ESD robustness. However, it should be further optimized to decrease its trigger voltage and meet the requirement for the bidirectional applications. In this paper, a new modified diode triggered bidirectional SCR is proposed, the layout area is reduced by commonly using the trigger diode. The clamp voltage is also reduced by changing the locations of the active regions. The proposed device was fabricated in a 28 nm CMOS technology. The experimental results show that the new proposed device has a symmetry I-V characteristic and a good ESD robustness.