Geometric Dependence of the Total Ionizing Dose Response of FinFETs

Abstract

The total ionizing dose induced degradation in advanced deep-submicron CMOS technologies has been significantly reduced by scaling. Damage to isolating field oxides remains a significant threat for integrated circuits fabricated in these technologies that must operate in harsh radiation environments. This work investigates the effects of geometry on the total ionizing dose response of bulk and Silicon-on-Insulator (SOI) FinFETs. Experimental and TCAD simulations show that the post-irradiation response of bulk FinFETs is dominated by buildup of charge in the shallow trench isolation oxide which induces a parasitic leakage current path, whereas in SOI FinFETs, charge trapping in Buried Oxide (BOX) usually is the primary contributing factor to device degradation in a radiation environment. For bulk FinFETs, the radiation-induced degradation increases with decreasing fin-width, increases with decreasing channel length, and increases with increasing fin-to-fin separation.