Evgeni Gousev

Thermal stability of polycrystalline silicon/metal oxide interfaces

The thermal stability of polycrystalline silicon (poly-Si)/ZrO2 interface was significantly enhanced when the poly-Si was plasma deposited using silane heavily diluted in He. With regard to this process, transmission electron microscopy shows a sharp poly-Si/ZrO2 interface that is stable at 1000u200a°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/ZrO2 interface when annealed at 1000u200a°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.