Electrical properties and reliability of HfO 2 gate-dielectric MOS capacitors with trichloroethylene surface pretreatment

Abstract

Trichloroethylene (TCE) pretreatment of Si surface prior to HfO 2 deposition is employed to fabricate HfO 2 gate-dielectric MOS capacitors. Influence of this processing procedure on interlayer growth, HfO 2/Si interface properties, gate-oxide leakage and device reliability is investigated. Among the surface pretreatments in NH 3, NO, N 2O and TCE ambients, the TCE pretreatment gives the least interlayer growth, the lowest interface-state density, the smallest gate leakage and the highest reliability. All these improvements should be ascribed to the passivation effects of Cl 2 and HCl on the structural defects in the interlayer and at the interface, and also their gettering effects on the ion contamination in the gate dielectric. © 2007 Chin. Phys. Soc. and IOP Publishing Ltd.