杂质分凝对FZ-Si单晶电阻率均匀性影响的研究

Investigation of the Resistivity Uniformity Influenced by Impurity Segregation in FZ-Si

对区熔Si单晶样品的轴向、径向以及生长界面的电阻率进行了测试,分析了影响电阻率均匀性的主要因素。结果表明,通常认为的影响电阻率均匀性的因素,并不是决定性因素。本文从FZ单晶在生长过程中,杂质在轴向和侧向分凝的角度进行分析,认为由于晶体原子的侧向生长,产生的杂质侧向分凝,是电阻率分布不均匀的主要原因。大量生产实验表明,生长过程中改变常规生长参数对提高均匀性的作用并不明显,要想从本质上提高电阻率径向均匀性,只能尝试非常规的技术。

The main factors influencing the resistivity uniformity was analyzed based on the resistivity testing results along both axis direction and radius direction. The analyzing results indicate that the general influencing factors for resistivity uniformity are not the crucial factors. The impurity lateral segregation as a result of the lateral growing of monocrystal was considered the main reason for the resistivity uniformity, and this conclusion based on the analysis resulted from the impurity segregation along both axis direction and lateral direction. A great deal of experiments indicate, for improving the resistivity uniformity, it is not taking obvious action by changing general growing parameters, and special ways should be taken to improve the resistivity uniformity essentially.