Fabrication of Large-Grained Polycrystalline Si Thin Films by Controlling Nucleation Sites on Glass Substrates

通过控制玻璃基底上的成核位点制备大晶粒多晶硅薄膜

基本信息

批准号：
16360070
负责人：
YASUTAKE Kiyoshi
金额：
$ 6.66万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360070/
关键词：
polycrystalline Si Si thin film glass substrate large-grain crystal nucleus Ge nano-crystal solid phase crystallization nano-imprint

项目摘要

Large-grained polycrystalline silicon (poly-Si) thin films on glass substrates are of interest for the fabrication of high-performance thin-film transistors (TFT) and cost-effective solar cells. To obtain large-grained poly-Si thin films, it is important to control the formation of nucleation sites for Si crystal growth on a glass surface prior to film deposition. Glass substrates having nucleation sites with tailored properties, such as size and spacing, are particularly desirable for the solid-phase crystallization (SPC) of amorphous silicon (a-Si) thin films. In this work, we have proposed a new process to fabricate crystalline Ge islands with controlled size and density in a tailored range to form nuclei for SPC of a-Si thin films. The process consists of the deposition of a-Ge thin films on glass substrates at room temperature, the subsequent vacuum annealing for SPC of the deposited a-Ge thin films to form self-assembled crystalline Ge islands, and the oxygen etching for controlling the size and density of Ge islands. From the micro beam reflection high-energy electron diffraction observation of the partially crystallized a-Si thin film using Ge nuclei, we have confirmed that Ge islands act as nuclei for Si crystallization. Marked reductions of the crystallization time and temperature are observed in the annealing experiments of a-Si : H thin films deposited on glass substrates with Ge nuclei. Moreover, it is found that the crystal growth rate of a-Si : H deposited by atmospheric pressure plasma CVD is much larger than that of a-Si deposited by E-beam evaporation. For the location control of Ge nuclei on glass substrates, a nano-imprint technique using crystalline Ge tip array has been demonstrated.

玻璃基板上的大晶粒多晶硅 (poly-Si) 薄膜对于制造高性能薄膜晶体管 (TFT) 和经济高效的太阳能电池很有意义。为了获得大晶粒多晶硅薄膜，在薄膜沉积之前控制玻璃表面硅晶体生长成核位点的形成非常重要。具有定制特性（例如尺寸和间距）的成核位点的玻璃基板对于非晶硅（a-Si）薄膜的固相结晶（SPC）是特别理想的。在这项工作中，我们提出了一种新工艺来制造尺寸和密度在定制范围内的晶体Ge岛，以形成a-Si薄膜SPC的核。该工艺包括在室温下在玻璃基板上沉积a-Ge薄膜，随后对沉积的a-Ge薄膜进行SPC真空退火以形成自组装晶体Ge岛，并通过氧蚀刻来控制尺寸和葛岛的密度。通过对使用Ge核的部分结晶a-Si薄膜的微束反射高能电子衍射观察，我们证实了Ge岛充当了Si结晶的核。在具有Ge核的玻璃基板上沉积的a-Si:H薄膜的退火实验中观察到结晶时间和温度显着降低。而且发现，常压等离子体CVD沉积的a-Si:H的晶体生长速率远大于电子束蒸发沉积的a-Si。为了控制玻璃基板上的Ge核的位置，已经演示了使用晶体Ge尖端阵列的纳米压印技术。