On MOSFET Threshold Voltage Extraction Over the Full Range of Drain Voltage Based on Gm/ID

TL;DR

This paper introduces an analytical method for extracting MOSFET threshold voltage across the entire drain voltage range, accounting for different device structures and operational modes, with improved consistency and ease of implementation.

Contribution

It presents a novel, fully analytical threshold voltage extraction technique applicable over the full drain voltage range, including effects of halo implants and moderate inversion.

Findings

Threshold voltage remains nearly constant for ideal MOSFETs across drain voltages.

Halo-implanted MOSFETs show increased threshold voltage at low drain voltages.

The method outperforms existing techniques in consistency and simplicity.

Abstract

A MOSFET threshold voltage extraction method covering the entire range of drain-to-source voltage, from linear to saturation modes, is presented. Transconductance-to-current ratio is obtained from MOSFET transfer characteristics measured at low to high drain voltage. Based on the charge-based modeling approach, a near-constant value of threshold voltage is obtained over the whole range of drain voltage for ideal, long-channel MOSFETs. The method reveals a distinct increase of threshold voltage versus drain voltage for halo-implanted MOSFETs in the low drain voltage range. The method benefits from moderate inversion operation, where high-field effects, such as vertical field mobility reduction and series resistances, are minimal. The present method is applicable over the full range of drain voltage, is fully analytical, easy to be implemented, and provides more consistent results when compared to existing methods.