Hot Carrier Effect on Gate-Induced Drain Leakage Current in n-MOSFETs with HfO2/Ti1-xNx Gate Stacks

Abstract

"This paper investigates the effect of channel hot carrier stress (CHCS) on gate-induced drain leakage (GIDL) current in n-type metal-oxide-semiconductor field effect transistor (n-MOSFETs) with HfO2/Ti1-xNx gate stacks. It was found that the behavior of GIDL current during CHCS has dependence with the interfacial layer (IL) oxide thickness of high-k/metal gate stacks. As IL thickness becomes thinner, the GIDL current has a gradual decrease during CHCS, which is contrary to the result of thick-oxide IL devices. Based on the variation of GIDL current (Delta I-GIDL) in different stress voltage across gate and drain terminals, trap-assisted band to band holes injection model was proposed to explain the different behavior of GIDL current for different IL thickness. Furthermore, we also investigated the impact of different Ti1-xNx composition of metal gate electrode on the Delta I-GIDL after CHCS, and observed that the magnitude of Delta I-GIDL decreases with the increase of nitride ratio. This is due to the fact that nitride atoms diffusing from the metal gate fill up oxygen vacancies, and reduce the concentration of traps in high-k dielectric. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.001206esl] All rights reserved."