Optimization of on-chip ESD protection structures for RF operations

Diodes are key components in on-chip electrostatic discharge (ESD) protection design. As the operating frequency of the microchip being protected against the ESD continues to increase, the parasitic capacitance associated with the diodes in the ESD structure starts to impose problems for RF operation. This paper presents a systematic approach to optimize the diode structure for minimal parasitic capacitance based on the requirements of breakdown voltage and heat dissipation. The device simulator Atlas, with mix-mode simulation capability, is calibrated against measurement data and used to carry out the optimization. An optimized diode structure with a parasitic capacitance of less than 30 fF at an operating frequency of 10 GHz and ESD charging voltage of 1 kV has been suggested.