Interface properties of annealed and nitrided HTO layers

Abstract

Non-contact measurements of interface state density and oxide charge were compared to surface recombination velocity measurements for their ability to provide a characterization of oxide–silicon interfaces. High-temperature deposited oxide (HTO) layers were used as the test vehicles. Both techniques are shown to agree quite well with each other and with the traditional capacitance–voltage technique. From the point-of-view of process characterization, interface state density is very high in as-deposited films, it is strongly reduced by annealing or nitridation and it is increased again by reoxidation. SIMS nitrogen profiles show that in nitrided HTO layers interface state density is strongly related to nitrogen concentration at the oxide–silicon interface.