Effects of annealing temperature on workfunction of MoOx at MoOx/SiO2 interface and process-induced damage in indium tin oxide/MoOx/SiOx/Si stack

Abstract

The workfunction of molybdenum oxide (MoOx) at the MoOx/SiO2 interface, which is referred to as the interface workfunction, and the process-induced damage at the SiO2/Si interface in an indium tin oxide (ITO)/MoOx/SiO2/Si structure are extracted by capacitance–voltage (C–V) analysis. The estimated interface workfunction is compared with that of the bulk determined by ultraviolet photoelectron spectroscopy (UPS). The interface workfunction of 5.59 eV for the as-grown ITO condition is 0.41 eV smaller than the bulk workfunction for the as-grown MoOx film. The reactive-plasma deposition (RPD) process induces damage at the SiO2/Si interface, with an estimated interface defect density (Dit) of 3.9 × 1011 cm−2 eV−1. The effects of postdeposition annealing in a forming gas on these parameters are also studied. The interface workfunction decreases with increasing temperature to 5.24 eV at 400 °C, while that of the bulk is 5.9 eV, suggesting a difference in the interface and bulk properties. The damage is almost removed at 250 °C.