Modeling and Characterization of Inconsistent Behavior of Gate Leakage Current with Threshold Voltage for Nano MOSFETs

Abstract

A strange relationship of gate leakage current and threshold voltage variation for nano MOSFETs is analyzed using factual strategy and subsequently a physical model is proffered. The gate leakage current increments with the threshold voltage before it diminishes at higher threshold voltage in nanoscale devices. This inconsistent behavior of gate leakage current with threshold voltage variations is precisely clarified in the manuscript through the concept of accord between two contrary operations: threshold voltage roll-off impact and gate leakage current reliance on surface potential. The tunneling gate leakage current density diminishes with threshold voltage over surface potential. However, the threshold voltage roll-off impact causes higher threshold voltage for larger channel length devices. The net gate leakage current is adjusted by these two contrary functions of threshold voltage. In addition, the rate of accretion of the gate leakage current with threshold voltage variation is also analyzed. The impact of the increase in the power supply voltage on the rate of accretion of the gate leakage current vs. threshold voltage curve is also explored. Thorough methodical TCAD simulations are accomplished to validate the proffered models. Both the experimental outcomes, TCAD simulations and physics based models are implemented to uncover and clarify the threshold voltage gate leakage relationship, particularly for nano MOSFETs. The proposed notion is not currently captured in conventional gate leakage nano device models, hence the proffered physical models may be utilized in progression of reliable and trustworthy TCAD simulation tools for nano devices.