ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The effect of exposing low-temperature-annealed chemical vapor deposited phosphosilicate glass films directly to water on the properties of such oxides has been studied. The capacitance-voltage (C-V) curves of these as-deposited oxides have been known to shift on annealing at temperatures in the range of 150–1000 °C in gaseous or vacuum ambients. It is found that when exposed to water, with the increasing duration of water exposure, the C-V curves of these annealed oxides gradually shift back, to the original preanneal location on the voltage axis. The effect, which is similar to the reported effect of water-related traps, is directly observed without using avalanche injection. The C-V recovery is, however, limited to oxides annealed at temperatures ≤450 °C. Hydrogen concentration analysis clearly associates these C-V shifts with changes in concentration resulting from an anneal in a gaseous ambient or to the water exposure. If, however, the oxides are dry annealed at temperatures of 500 °C or higher, the C-V recovery, on water exposure, is very small. So is the increase in the hydrogen concentration, confirming the role of the hydrogenous species in the oxide. The results also suggest a structural change in the oxide occurring at temperatures above 500 °C and leading to oxides that have much lower water solubility compared to that in as-deposited oxides or oxides annealed at temperatures ≤450 °C. Possible mechanisms of oxide charge generation are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.351498
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