Effective Channel Length and Source-Drain Series-Resistance Determination after Electrical Gate Length Verification of Metal-Oxide-Semiconductor Field-Effect Transistor

Abstract

A new technique of determining the effective channel length by directly measuring source-drain series resistance of metal-oxide-semiconductor field-effect transistors (MOSFETs) was proposed. By using MOSFETs with scaled gate lengths, the source-drain series resistance can be obtained from a device whose source and drain regions are connected. In order to determine whether a MOSFET's source and drain are connected, a `difference of total resistance' (DTR) method, which can also be used to electrically determine the gate length of a normal MOSFET after the fabrication process, was developed in this study. The effective channel length can then be extracted from the obtained series resistance and I–V of MOSFETs. This technique, although it requires very short-gate-length devices, is not affected by source-drain series-resistance gate bias dependence issue encountered in conventional I–V methods.