Thermal stability of polycrystalline silicon/metal oxide interfaces

Abstract

The thermal stability of polycrystallinesilicon ( poly-Si )/ ZrO 2 interface was significantly enhanced when the poly-Si was plasmadeposited using silane heavily diluted in He. With regard to this process, transmission electron microscopy shows a sharp poly- Si/ZrO 2 interface that is stable at 1000 °C. When the poly-Si was deposited by chemical vapor deposition using undiluted silane gas, transmission electron microscopy shows strong reactions at the poly- Si/ZrO 2 interface when annealed at 1000 °C. The increased stability can be attributed to He dilution, which may prevent hydrogen from reducing the metal oxide. Another explanation may be directly related to He-excited plasma, which is known to produce denser and more stable films.