【摘要】：冶金法制備多晶硅是太陽能電池領(lǐng)域具有發(fā)展前景的制備工藝,在硅片和器件制造過程中,作為過渡族金屬之一的銅(Cu)元素可能會(huì)沾污硅片。所以本論文提出對(duì)冶金法制備的多晶硅進(jìn)行銅沉淀行為研究,對(duì)太陽能電池硅材料的開發(fā)和應(yīng)用具有實(shí)際意義和應(yīng)用價(jià)值。 本論文以實(shí)驗(yàn)室自制的冶金法多晶硅片作為硅基材料,對(duì)該多晶硅片進(jìn)行銅沉淀實(shí)驗(yàn)的研究。研究了不同狀態(tài)的銅雜質(zhì)在熱處理過程中的銅沉淀行為：并研究在熱處理溫度、退火時(shí)間、冷卻速率和退火氣氛等不同熱處理?xiàng)l件下多晶硅中的銅沉淀行為,并研究了P擴(kuò)散對(duì)銅沉淀行為的影響,利用四探針電阻測(cè)試儀測(cè)量銅沉淀前后的電阻率,少子壽命測(cè)試儀測(cè)量多晶硅片的少子壽命,掃描電子顯微鏡測(cè)試多晶硅片的表面形貌及雜質(zhì)分布。 采用磁控濺射法和溶液浸漬法分別在多晶硅片的未拋光面覆蓋銅單質(zhì)和銅化合物,將其分別在管式退火爐中進(jìn)行退火處理,所得的銅沉淀樣品電學(xué)性能均有所下降。不同的銅雜質(zhì)狀態(tài)在多晶硅中的銅沉淀行為不同,由單質(zhì)銅直接引入銅雜質(zhì)更容易形成銅沉淀。在該過程中,表面有銅沉淀析出的溫度為700℃。對(duì)于常規(guī)的管式退火爐進(jìn)行銅沉淀實(shí)驗(yàn)而言,在快速熱退火爐中進(jìn)行銅沉淀實(shí)驗(yàn),更加容易形成銅沉淀,影響多晶硅的電學(xué)性能。 在不同的熱處理?xiàng)l件進(jìn)行銅沉淀實(shí)驗(yàn)的研究。在500℃、700℃、900℃、1000℃和1100℃退火條件下,隨著退火溫度的升高,多晶硅中更容易形成銅沉淀；在0.5min,1min,2min,5min和10min的退火時(shí)間下進(jìn)行銅沉淀,發(fā)現(xiàn)在5min多晶硅表面有明顯的銅沉淀生成；在慢速冷卻的條件下,由于有足夠的時(shí)間擴(kuò)散到沉淀區(qū)域,相比于在快速冷卻的條件下,更容易在多晶硅中形成銅沉淀；在氬氣和空氣的不同氣氛下進(jìn)行退火處理,由于在氬氣氣氛下,多晶硅會(huì)生成空穴等相關(guān)缺陷,從而促進(jìn)銅沉淀的形成,影響硅片的性能。 對(duì)多晶硅片進(jìn)行重復(fù)銅沉淀實(shí)驗(yàn)的研究,不斷升高銅沉淀的溫度,由于銅沉淀形成的驅(qū)動(dòng)化學(xué)勢(shì)降低,促進(jìn)銅沉淀的形成；按0.5min,1min,2min,5min和10min不斷延長多晶硅片的退火時(shí)間,在5min以內(nèi)銅沉淀含量增加,但當(dāng)5min后銅沉淀達(dá)到飽和,繼續(xù)延長時(shí)間,表面形貌不會(huì)發(fā)生明顯改變。 因此,在多晶硅的生產(chǎn)和應(yīng)用過程中,要避免多晶硅及器件在高溫條件下長時(shí)間與銅源接觸和使用,在實(shí)際過程中進(jìn)行磷擴(kuò)散能形成吸雜層,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，

本文編號(hào)：2215901