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使用快速热化学气相沉积(RTCVD)系统在石英衬底上制备了多晶硅薄膜,并利用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等对其微结构进行了研究.XRD谱显示单个很强的(220)衍射峰,说明多晶硅薄膜表面具有<110>择优取向.表面SEM照片表明多晶硅薄膜的表面由大量尺寸不等的多边棱锥形晶粒组成,断面SEM照片则说明多晶硅薄膜内的晶粒沿垂直于衬底的方向柱状生长.TEM结果进一步揭示了多晶硅薄膜内存在包括一次孪晶、二次孪晶以及三次以上的高次孪晶在内的大量孪晶.以上实验结果无法用对常压化学气相沉积(APCVD)法制备多晶硅薄膜的生长习性的传统观点解释,但是却可以由Ino等人提出的关于面心立方金属薄膜中高次孪晶形成和发展的模型很好的解释.根据以上实验结果和Ino的模型,认为RTCVD在石英衬底上沉积多晶硅薄膜的成核、生长是以形成高次孪晶粒子为基础的,然后这些高次孪晶粒子以岛状生长的模式连成薄膜.
A polycrystalline silicon thin film was prepared on a quartz substrate by a rapid thermal chemical vapor deposition (RTCVD) system and its microstructure was studied by XRD, SEM and TEM. .XRD spectra showed a single strong (220) diffraction peak, indicating that the polycrystalline silicon thin film surface has a <110> preferred orientation. SEM images of the surface show that the surface of the polycrystalline silicon film is composed of a large number of polygonal pyramidal grains with different sizes. Indicating that the grains in the polycrystalline silicon film grow in a columnar direction perpendicular to the substrate, and the TEM results further reveal that there are a large number of twins in the polycrystalline silicon film including one twins, two twins and more than three high-order twins. The above experimental results can not be explained by the conventional view of the growth habit of polycrystalline silicon films prepared by atmospheric pressure chemical vapor deposition (APCVD), but the model proposed by Ino et al. For the formation and development of high-order twins in face-centered cubic metal films A good explanation.According to the above experimental results and Ino’s model, RTCVD that the deposition of polycrystalline silicon thin film on a quartz substrate nucleation, the growth is the formation of high-level twin Based on the grain-particles, these high-order twin particles are then linked into thin films in the form of islands.