Monitoring of FinFET Characteristics Using ΔVDIBLSS/(Ion/Ioff) and ΔVDIBL/(Ion/Ioff)

Abstract

In this paper, we present a descriptive analysis of a performance index, ΔVDIBLSS/(Ion/Ioff), used for performance monitoring. Scaled n- and p-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) (planar and FinFET devices) are included for comparison of performance trends. Also, the simplified ΔVDIBL/(Ion/Ioff) for monitoring the electrical characteristics of MOSFET devices is proposed due to the "quick measurements" required in the last step of the semiconductor manufacturing process. ΔVDIBL/(Ion/Ioff) only accounts for drain-induced barrier lowering in its numerator and on/off current ratio in its denominator. The calculation process for ΔVDIBL/(Ion/Ioff) is much quicker than for ΔVDIBLSS/(Ion/Ioff), where we need to make an extra measurement of the value of the subthreshold swing. Performance metrics, such as Ion/Ioff and intrinsic gain, gm × ro, are reported using ΔVDIBLSS/(Ion/Ioff) and ΔVDIBL/(Ion/Ioff). ΔVDIBLSS of about 100 mV in scaled MOSFETs is required to ensure that the gate control is strong. Since Ion/Ioff is a sensitive function of threshold voltage, the estimates of the ΔVDIBLSS/(Ion/Ioff) and ΔVDIBL/(Ion/Ioff) are therefore dependent on the design of threshold voltage. In planar MOSFETs, small values of ΔVDIBLSS/(Ion/Ioff) and ΔVDIBL/(Ion/Ioff) are hard to achieve. However, in FinFETs, it is easy to achieve the performance requirements due to its tri-gate structure.