Hydrogen diffusion through silicon/silicon dioxide interfaces

In order to improve the electrical properties of semiconductor devices resi dual defects have to be passivated. In c-Si metal-oxide-semiconductor devic es, these defects are located at the Si/SiO2 interface, while in polycrysta lline silicon thin-film transistors, in addition to interface defects, grai n-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 unde rstand H transport through Si/SiO2 interfaces. H transport through the oxid e was studied by measuring the changes of the flux through the oxide as a f unction 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 t he oxide thickness. This indicates that the striking decrease in Il flux is not due to an increase in barrier height. (C) 2000 American Vacuum Society .