Structural nature of the N-2 RIE plasma induced slow states and bulk trapsin thin SiO2-Si structures

Reactive ion etching (RIE) damage effects on thin (13 nm) thermal SiO2 on S i have been studied. The comparative analyses of the electrical and XPS res ults show that 5-min exposure to N-2 plasma operating in RIE mode generates positive charge Q(ot) in the form of slow states ( similar to 2.5 x 10(12) cm(-2)) and bulk traps ( similar to 1.3 x 10(12) cm(-2)). Bulk traps are n ot uniformly distributed throughout the oxide, their density being greater near the Si-SiO2 interface. Q(ot) plays; a key role in electron transport t hrough the oxide causing pretunneling leakage current enhancement. I;:IE pr ocess favors the generation of constant amount of SiO species through the w hole oxide and increases the amount of the three intermediate oxidation sta tes of Si, namely Si1+, Si2+, Si3+, in the transition interfacial region. A broadening of this region after RIE treatment is also detected. It is esta blished that these three intermediate oxidation states of Si are the precur sors of the detected slow states whereas the SiO species in the bulk of the oxide account for the bulk traps. (C) 2000 Elsevier Science S.A. All right s reserved.