A dc I-V model for short-channel polygonal enclosed-layout transistors

Despite the demonstrated radiation immunity of gate-enclosed layout transistors in deep submicron CMOS technologies, there is a significant lack of a thorough theoretical study addressing fundamental design issues on this kind of transistors. In this paper we propose a physical dc I –V model for short-channel polygonal-shape enclosed-layout transistors in both the linear and saturation regions of operation accounting for second-order effects such as depletion region non-uniformity, carrier velocity and channel length modulation. The impact of this layout style on the driving capability of the devices is also investigated. Experimental results based upon a fabricated NMOS test chip containing these devices in a standard 0.18m CMOS technology process are presented. The comparison of the theoretical prediction with the experimental data show close agreement.

keywords: Enclosed-layout transistors (ELT), radiation-hardness, modelling, deep submicron CMOS, short-channel effects