High-Robustness And Low-Capacitance Silicon-Controlled Rectifier For High-Speed I/O Esd Protection

A high-robustness and low-capacitance clamp for on-chip electrostatic discharge (ESD) protection is developed. The low capacitance is obtained by mitigating the capacitance associated with the lightly doped n-well/p-well junction. In addition to minimizing the capacitance, the high ESD robustness is achieved by optimizing independently within the same structure a silicon-controlled rectifier and a diode for the forward and reverse conduction processes, respectively. The new clamp with an area of 50 ×10μm 2 is able to handle an ESD current in excess of 1.5 A, whereas the capacitance at zero bias is kept at 94 fF. © 1980-2012 IEEE