Science Letters： A robust polysilicon-assisted SCR in ESD protection application

A novel polysilicon-assisted silicon-controlled rectifier （SCR） is presented and analyzed in this paper, which is fabricated in HHNEC＇s 0.18μm EEPROM process. The polysilicon-assisted SCRs take advantage of polysilicon layer to help bypass electro-static discharge （E S D） current without occupying extra layout area. TLP current-voltage （I-V） measurement results show that given the same layout areas, robustness performance of polysilicon-assisted SCRs can be improved to 3 times of conventional MLSCR＇s. Moreover, one-finger such polysilicon-assisted SCRs, which occupy only 947 [3mz layout area, can undergo 7-kV HBM ESD stress. Results further demonstrate that the S-type I-V characteristics of polysilicon-assisted SCRs are adjustable to different operating conditions by changing the device dimensions. Compared with traditional SCRs, this new SCR can bypass more ESD currents and consumes smaller IC area.