Electrical properties and reliability of HfO₂ gate-dielectric MOS capacitors with trichloroethylene surface pretreatment

Trichloroethylene (TCE) pretreatment of Si surface prior to HfO₂ deposition is employed to fabricate HfO₂ gate-dielectric MOS capacitors. Influence of this processing procedure on interlayer growth, HfO₂/Si interface properties, gate-oxide leakage and device reliability is investigated. Among the surface pretreatments in NH₃, NO, N₂O 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 Cl₂ 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.