Electrical gate length measurement test structure for short channel MOSFET characteristics evaluation

Abstract

The electrical characteristics and gate lengths of individual MOSFETs are evaluated by a test structure with a Kelvin pattern as the gate electrode. The gate length measurement by SEM can be substituted by the electrical measurement using this test structure. Excellent correspondence is obtained between the threshold voltage lowering in the short channel region and the electrically measured gate length. Furthermore, the precision of drain-to-gate overlap length is improved by applying the effective channel length extraction method to the electrically measured gate length instead of the commonly used designed gate length.