Scaling Study of Contact Operation at Constant Current in Oxide Semiconductor Field-Effect Transistors

An improved methodology that can precisely reflect the metal-semiconductor contact behavior is developed for oxide semiconductor field-effect transistors (OS FETs). In contrast to the conventional transfer length method, where the extraction is performed at a constant drain voltage condition, an optimized constant current scheme is alternatively proposed to account for a non-constant series resistance ( R SD ). The modified technique enables one to unveil the underlying device physics at the metal‑OS interface from a field‑effect configuration. Additionally, the resistance of contact and extension regions can be independently differentiated by the present method. The analysis further highlights the significant role of contact resistance in OS FETs.