Journal of Vacuum Science & Technology B, Vol.18, No.3, 1770-1772, 2000
Hydrogen diffusion through silicon/silicon dioxide interfaces
In order to improve the electrical properties of semiconductor devices residual defects have to be passivated. In c-Si metal-oxide-semiconductor devices, these defects are located at the Si/SiO2 interface, while in polycrystalline silicon thin-film transistors, in addition to interface defects, grain-boundary defects have to be passivated. In both device structures, H has to diffuse through numerous layers of oxides, silicon, and possible surface barriers. To improve the H passivation efficiency, it is important to understand H transport through Si/SiO2 interfaces. H transport through the oxide was studied by measuring the changes of the flux through the oxide as a function of time, temperature, and oxide thickness. The oxide layer reduces the H flux into the underlying layers by more than four orders of magnitude. The temperature dependence of the H flux was found to be independent of the oxide thickness. This indicates that the striking decrease in Il flux is not due to an increase in barrier height.
Keywords:POLYCRYSTALLINE SILICON