Evaluation of Hot-Hole-Induced Interface Traps at the Tunnel-SiO2(3.5 nm)/Si Interface by the Conductance Technique

Hot-hole-induced interface degradation in ultrathin (3.5 nm) oxides has been evaluated by the small-signal AC conductance technique. To degrade the tunnel-SiO2/Si interface, holes are injected by the avalanche technique. The conductance technique makes it possible to estimate the number of interface traps even when there are a large intrinsic tunneling leakage before injection and a large stress-induced leakage current after injection. Experimental results show that holes can create acceptor-like interface traps at the tunnel-SiO2/Si interface and that the conventional reliability test comprising carrier injection and interface-trap estimation is still applicable to oxides as thin as 3.5 nm.