溶液法铝诱导晶化多晶硅薄膜

介绍了一种基于溶液的廉价制备Al诱导晶化多晶硅薄膜的方法. 先以低压化学气相沉积(LPCVD)方法制备50 nm厚的非晶硅(amorphous silicon, a-Si)薄膜作为前驱物, 通过旋涂的方法, 将含有Al的盐溶液涂覆在a-Si薄膜表面, 550-620 ℃下氮气氛围退火若干小时得到多晶硅薄膜. 文中针对化学诱导源的种类、前驱物表面状况对晶化效果的影响进行了研究. 发现只有反应生成物中含有偏铝酸根(AlO-2)的碱性溶液才能发生诱导晶化, 而若Al溶液浓度过低, 则不能得到连续的多晶硅薄膜. a-Si表面若附有薄氧化层会有利于Al盐溶液在表面上的粘附以及得到大尺寸的晶粒, 然而又会增高退火晶化所需要的温度. 同时溶液在薄膜表面的粘附状况还会受到溶液中存在的其它离子的影响. 因此必须选用合适的实验条件.

Al-Induced Crystallization of Polycrystalline Silicon Thin Films Based on Solution Method

A new low-cost method to prepare polycrystalline silicon thin films by solution-based aluminum-induced crystallization (AIC) was introduced in this article. Amorphous silicon (a-Si) thin films with 50 nm thickness were deposited by low-pressure chemical vapor deposition (LPCVD) and used as the precursors of crystallization. Aluminate solution with several components was spun on the surface of the a-Si films. Crystallization was accomplished at the annealing temperature between 550 and 620 ℃ for several hours in furnace and N2 ambience. The crystallization effect was dependent on the aluminumconcentration in aluminate solution and the surface status of the studied a-Si films. We found that the AIC process could take place only with solution containing meta-aluminates, and continuous polycrystalline silicon thin films could be obtained if the solution concentration was not too low. The natural oxide layers on the surface of a-Si films were good for adhesion of aluminate solution to the films and the formation of larger grains, but would lead to a higher crystallization temperature. In addition, various micrographic patterns taken fromthe crystallized films were observed, which were resulted from different kinds of Al-salt solution as the source for AIC. In one word, it was important to choose appropriate experiment parameters.