退火对Ge诱导晶化多晶Si薄膜结晶特性的影响

摘要

本文采用磁控溅射法，衬底温度500℃下在硅衬底上分别制备具有Ge填埋层的a—Si／Ge薄膜和a-Si薄膜，并进行后续退火，采用Raman光谱、X射线衍射、原子力显微镜及场发射扫描电镜等对所制薄膜样品进行结构表征．结果表明，Ge有诱导非晶硅晶化的作用，并得出以下重要结论：衬底温度为500℃时生长的a—Si／Ge薄膜，经600℃退火5hGe诱导非晶硅薄膜的晶化率为44％，在相同的退火时间下退火温度提高到700℃，晶化率达54％．相同条件下，无Ge填埋层的a-Si薄膜经800℃退火5h薄膜实现晶化，晶化率为46％．通过Ge填埋层诱导晶化可使在相同的条件下生长的非晶硅晶薄膜的晶化温度降低约200℃．Ge诱导晶化多晶Si薄膜在Si（200）方向具有高度择优取向，且在此方向对应的晶粒尺寸约为76nm．通过Ge诱导晶化制各多晶Si薄膜有望成为制备高质量多晶Si薄膜的一条有效途径．%In this paper, an a-Si/Ge thin film with a buried layer of Ge and an a-Si thin film are prepared on Si substrates at a temperature of 500 ℃ by magnetron sputtering. The prepared films are annealed for 5h at different temperatures in vacuum. The annealed films are characterized by Raman scattering, X-ray diffraction, atomic force microscope and field emission scanning electron microscope. The results reveal that Ge can induce amorphous Si (a-Si) growing at a temperature of 500 ℃ by magnetron sputtering crystallize after annealing at a temperature of 600 ℃ for 5h. And in the a-Si/Ge thin film the degrees of crystallization of a-Si are 44% and 54% at the annealing temperatures of 600 ℃ and 700 ℃, respectively. By comparison, a-Si thin film without Ge is crystallized at an annealing temperature of 800 ℃ for 5h and the degree of crystallization is 46%. The crystallization temperature of a-Si/Ge is reduced by 200 ℃ compared with that of a-Si film without buffed Ge layer in the film. The prepared poly-Si thin film possesses high Si(200) orientation with a grain size of 76 nm. The preparation of poly-Si film by Ge-induced crystallization might be a useful technology for developing high-quality poly-Si film.