On-chip ESD protection design for GHz RF integrated circuits by using polysilicon diodes in sub-quarter-micron CMOS process

ESD protection in RF integrated circuits has several considerations: low parasitic capacitance, constant input capacitance, and insensitive to substrate coupling noise. In this paper, a new ESD protection design with polysilicon diodes for RF IC applications is proposed and characterized. The proposed polysilicon diode is constructed by a polysilicon layer in a general CMOS process with a central un-doped region. The polysilicon diode with variation on the width of the central un-doped region is characterized at different temperatures. An on-chip ESD protection circuit realized with the stacked polysilicon diodes to reduce the total input capacitance for GHz RF application is demonstrated.