热丝法制备多晶硅薄膜晶体取向及形态的研究

Growth Orientation of Poly-Si Film by Hot-Wire Chemical Vapor Deposition

采用热丝化学气相沉积法（HWCVD），在很近的热丝与衬底距离（5mm）下沉积多晶硅薄膜，研究了热丝温度、SiH4浓度对多晶硅晶粒取向和晶粒尺寸的影响规律。结果表明：当热丝温度在1400oC～1800oC变化，衬底温度225℃-320℃时，沉积出多晶硅薄膜的择优取向随温度升高的变化规律是（111）→（220）→（111）；在低的灯丝温度（-1450℃）和低的衬底温度（235℃）条件下，获得了晶粒横向尺寸大于1μm、垂直尺寸大于5μm的均匀致密的多晶硅薄膜。

Polycrystalline silicon（poly-Si） films were grown by hot-wire chemical deposition（HWCVD） with the substrates heated by direct radiation of the hot-filament 5 mm away. The films were characterized with X-ray diffraction（XRD） and scanning electron microscopy （SEM） .The results show that the preferential growth orientation and the grain sizes of the poly-Si significantly depend on the temperatures of the filament and substrate; but are insensitive to the silane concentration in the partial pressure range of 1% - 5 % [ SiH4/SiH4＋ H2 ]. For instance,as the temperature of the substrates, heated by the hot-filament varying from 1400 ℃ to 1800 ℃,rises up from 225 ℃ to 320℃,the preferred growth orientation of the poly-Si changes from （ 111 ） into （220） and back into （ 111 ） direction again. Grown at a low filament temperature of 1450℃ and a substrate temperature of 235℃ ,the averaged size of ellipsoid-shaped grains,approximately 1μm wide and 5 μm long, were observed on the surface of fairly uniform and compact poly-Si films.