Analysis on Self Heating Effect for a Trenched Source/Drain Structure in Triple-Stacked Nanowire FET.

Accurate evaluations of self-heating effects (SHEs) in highly down-scaled devices have become essential for improved performance and reliability of such devices. In this paper, SHEs in a triplestacked nanowire FETs (NWFETs) with trenched source drain structures, a structure which may be capable of obtaining a high on-current (Ion) in the 5 nm node, were analyzed through TCAD simulations. It was confirmed that trench methods for triple-stacked devices can effectively boost Ion if disregarding SHEs. However, because SHEs generated under high Ion prevent any increase of Ion, the trench steps should be adjusted appropriately considering the balance between the contact resistance and the SHEs. In order to obtain a proper trench depth, several steps were compared through a simulation. To support the results, the thermal resistance (Rth) was used in the comparison.