MICROSCOPIC NATURE OF BORDER TRAPS IN MOS OXIDES

We show that enhanced hole-, electron-, interface-, and border-trap ge neration in irradiated Si/SiO2/Si systems that have received a high-te mperature anneal during device fabrication is related either directly, or indirectly, to the presence of anneal-created oxygen vacancies. Th e high-temperature anneal results are shown to be relevant to understa nding defect creation in zone-melt-recrystallized silicon on insulator materials. We observe the electron paramagnetic resonance (EPR) of tr ap-assisted hole transfer between two different oxygen vacancy-type de fects (E'(delta)-->E'(gamma) precursor) in hole injected thermal SiO2 films. Upon annealing the hole injected Si/SiO2 structures at room tem perature, the E'(delta) center transfers its hole to a previously neut ral oxygen vacancy (O-3=Si-Si=O-3) site forming an E'(gamma) center. T his process, also monitored electrically, shows a concomitant increase in the border-trap density that mimics the growth kinetics of the tra nsfer-activated E'(gamma) centers. This suggests that both effects are correlated and that some of the transfer-created E'(gamma) centers ar e the entities responsible for the border traps in these devices. One implication of these results is that delayed defect growth processes c an occur via slow trap-assisted hole motion in SiO2.