Effect of Heavy Ion Irradiation on the RF Performance of 0.18μm Bulk Si MOSFETs

Abstract

In this work, the radio frequency (RF) performance degradation of very-deep-submicron (UDSM) MOSFETs induced by heavy-ion irradiation is investigated. Both the static characteristics and S-parameters are evaluated for 0.18μm bulk Si CMOS devices after exposure to heavy ions. The gate-to-source capacitance, gate-to-drain capacitance and source/drain series resistance after irradiation show significant shift. It can be explained by the fluctuation in potential and the dopant concentration which is introduced by displacement damage near LDD regions in the channel. Moreover, the cut-off frequency (fT) is also reduced due to the combined effect of transconductance degradation and gate capacitance change, which will reduce the circuit operation speed and may affect the input and output matching in key RF circuits. The characterization of the ion strike location in the channel region is also discussed in this paper.