Temperature-Dependent Electrical Properties of nMOSFETs With Different Thickness Al2O3 Capping Layer and TiN Gate

Abstract

In this article, the electrical properties of nMOSFET devices with different high-k Al2O3 capping layer thickness and TiN electrode have been systematically studied at deep cryogenic temperatures ranging from 10 to 300 K. The threshold voltage V-TH, transconductance g(m), carrier mobility mu, mobility attenuation factor theta, and subthreshold swing (SS) are extracted using the I-DS-V-GS curves and Y-function method at different temperatures. It is indicated that: 1) all the electrical parameters (V-TH, g(m), mu, theta, and SS) show strong temperature dependence in the range of studied temperatures and 2) temperature-dependent electrical properties of nMOSFET devices will modulate at various cryogenic temperatures ascribed to the presence of the Al2O3 capping layer on the SiO2 dielectric layer, which increases the oxide trap density and consequentially adjusts the threshold voltage and mobility of the devices.