Test Structures for Accurate UHF C-V Measurements of Nano-Scale CMOSFETs with HfSiON and TiN Metal Gate

Test structures for accurate UHF capacitance-voltage (C-V) measurements of high performance CMOSFETs with Hf-based high-k dielectric and TiN metal gate are analyzed. It is shown that series resistance or substrate resistance between the channel region and body contact plays a role in UHF C-V measurements. The substrate resistance beneath the gate region also impacts accurate UHF C-V measurements. Therefore, minimization of series resistance through short gate lengths with a minimum distance between the source/drain and body contact is highly desired for an accurate evaluation of gate dielectric thickness using UHF C-V measurements.