冶金法多晶硅铜沉淀行为研究
发布时间：2018-08-31 19:11
【摘要】：冶金法制备多晶硅是太阳能电池领域具有发展前景的制备工艺,在硅片和器件制造过程中,作为过渡族金属之一的铜(Cu)元素可能会沾污硅片。所以本论文提出对冶金法制备的多晶硅进行铜沉淀行为研究,对太阳能电池硅材料的开发和应用具有实际意义和应用价值。 本论文以实验室自制的冶金法多晶硅片作为硅基材料,对该多晶硅片进行铜沉淀实验的研究。研究了不同状态的铜杂质在热处理过程中的铜沉淀行为：并研究在热处理温度、退火时间、冷却速率和退火气氛等不同热处理条件下多晶硅中的铜沉淀行为,并研究了P扩散对铜沉淀行为的影响,利用四探针电阻测试仪测量铜沉淀前后的电阻率,少子寿命测试仪测量多晶硅片的少子寿命,扫描电子显微镜测试多晶硅片的表面形貌及杂质分布。 采用磁控溅射法和溶液浸渍法分别在多晶硅片的未抛光面覆盖铜单质和铜化合物,将其分别在管式退火炉中进行退火处理,所得的铜沉淀样品电学性能均有所下降。不同的铜杂质状态在多晶硅中的铜沉淀行为不同,由单质铜直接引入铜杂质更容易形成铜沉淀。在该过程中,表面有铜沉淀析出的温度为700℃。对于常规的管式退火炉进行铜沉淀实验而言,在快速热退火炉中进行铜沉淀实验,更加容易形成铜沉淀,影响多晶硅的电学性能。 在不同的热处理条件进行铜沉淀实验的研究。在500℃、700℃、900℃、1000℃和1100℃退火条件下,随着退火温度的升高,多晶硅中更容易形成铜沉淀；在0.5min,1min,2min,5min和10min的退火时间下进行铜沉淀,发现在5min多晶硅表面有明显的铜沉淀生成；在慢速冷却的条件下,由于有足够的时间扩散到沉淀区域,相比于在快速冷却的条件下,更容易在多晶硅中形成铜沉淀；在氩气和空气的不同气氛下进行退火处理,由于在氩气气氛下,多晶硅会生成空穴等相关缺陷,从而促进铜沉淀的形成,影响硅片的性能。 对多晶硅片进行重复铜沉淀实验的研究,不断升高铜沉淀的温度,由于铜沉淀形成的驱动化学势降低,促进铜沉淀的形成；按0.5min,1min,2min,5min和10min不断延长多晶硅片的退火时间,在5min以内铜沉淀含量增加,但当5min后铜沉淀达到饱和,继续延长时间,表面形貌不会发生明显改变。 因此,在多晶硅的生产和应用过程中,要避免多晶硅及器件在高温条件下长时间与铜源接触和使用,在实际过程中进行磷扩散能形成吸杂层,改善多晶硅的性能。
[Abstract]:The preparation of polycrystalline silicon by metallurgical method is a promising process in the field of solar cells. In the process of fabrication of silicon wafers and devices copper (Cu) as one of the transition metals may contaminate the silicon wafers. Therefore, the copper precipitation behavior of polysilicon prepared by metallurgical process is studied in this paper, which has practical significance and application value for the development and application of silicon materials for solar cells. In this paper, the polysilicon wafer made in the laboratory was used as the silicon based material, and the copper precipitation experiment was carried out on the polysilicon wafer. The copper precipitation behavior of copper impurity in different states during heat treatment was studied. The copper precipitation behavior in polycrystalline silicon was studied under different heat treatment conditions such as heat treatment temperature, annealing time, cooling rate and annealing atmosphere. The influence of P diffusion on the copper precipitation behavior was studied. The resistivity before and after copper precipitation was measured by four-probe resistance tester and the minority carrier lifetime test instrument was used to measure the minority carrier lifetime of polysilicon wafer. The surface morphology and impurity distribution of polysilicon wafer were measured by scanning electron microscope (SEM). Copper and copper compounds were coated on the unpolished surface of polysilicon wafer by magnetron sputtering and solution impregnation, respectively. The copper precipitates were annealed in a tube annealing furnace, and the electrical properties of the copper precipitated samples were decreased. The copper precipitation behavior of different copper impurity states in polycrystalline silicon is different. It is easier to form copper precipitate by introducing copper impurity directly from simple copper. In this process, the precipitation temperature of copper precipitates on the surface is 700 鈩，
本文编号：2215901
[Abstract]:The preparation of polycrystalline silicon by metallurgical method is a promising process in the field of solar cells. In the process of fabrication of silicon wafers and devices copper (Cu) as one of the transition metals may contaminate the silicon wafers. Therefore, the copper precipitation behavior of polysilicon prepared by metallurgical process is studied in this paper, which has practical significance and application value for the development and application of silicon materials for solar cells. In this paper, the polysilicon wafer made in the laboratory was used as the silicon based material, and the copper precipitation experiment was carried out on the polysilicon wafer. The copper precipitation behavior of copper impurity in different states during heat treatment was studied. The copper precipitation behavior in polycrystalline silicon was studied under different heat treatment conditions such as heat treatment temperature, annealing time, cooling rate and annealing atmosphere. The influence of P diffusion on the copper precipitation behavior was studied. The resistivity before and after copper precipitation was measured by four-probe resistance tester and the minority carrier lifetime test instrument was used to measure the minority carrier lifetime of polysilicon wafer. The surface morphology and impurity distribution of polysilicon wafer were measured by scanning electron microscope (SEM). Copper and copper compounds were coated on the unpolished surface of polysilicon wafer by magnetron sputtering and solution impregnation, respectively. The copper precipitates were annealed in a tube annealing furnace, and the electrical properties of the copper precipitated samples were decreased. The copper precipitation behavior of different copper impurity states in polycrystalline silicon is different. It is easier to form copper precipitate by introducing copper impurity directly from simple copper. In this process, the precipitation temperature of copper precipitates on the surface is 700 鈩，
本文编号：2215901
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