杨德仁铸造多晶硅的缺陷.ppt

Flux of oxygen 磷吸杂 铸造多晶硅的缺陷 杨 德 仁 浙江大学硅材料国家重点实验室 Muticrystalline Silicon 杂质 缺陷 间隙氧 替位碳 过渡金属杂质（Fe、Cu、Ni、Cr） 微缺陷 位错 晶界 影响电池效率!!! 硅晶体的杂质和缺陷 氧在硅熔体中的传递示意图 Raw materials Quartz crucibles 硅晶体中的氧 Solar Energy Material and Solar Cells, Vol.62, 37(2000). Oxygen clusters Solid State Phenomena, Vol. 82, 2002, P.707-712 Experimental Oi profile in growth direction and simulated Oi profile according to Pfann’s law (segregation coefficient 1.25). Diffusion from melt to surface （CL、CS is oxygen concentration in melt and solid near interface, respectively） Reaction in the surface of melt； （PS、PP is equilibrium pressure of SiO in the surface and the pressure in furnace Evaporation of SiO from surface （X＝Keff＋DL/(δL－G×V)－1） A=AL-S=AL-G ；CL=CS/Keff： 氧扩散模型 Experimental Oi profile in growth direction and simulated Oi profile on the basis of our model. Simulated Oi profile as a function of the exponent X. Solar Energy Material and Solar Cells, (2007), in print Interstitial oxygen concentrations of samples annealed for 24 h vs. annealing temperature. Solar Energy Materials and Solar Cells, Vol.72, 541(2002) Oxygen conc of the annealed mc-B and Cz samples 1150?C 950?C FTIR spectra of the mc-B samples annealed for 24 h. Solar Energy Materials and Solar Cells, Vol.72, 133(2002) 硅晶体中的金属杂质 Lifetime distribution of minor carriers Minority carrier lifetime mapping (a) and optical photograph (b) of a selected region of the sample treated by RTP at 900℃. Figure (c) is the lifetime of the region 1 and 2 shown in Fig. 4a before and after RTP at 900℃. 硅晶体位错 硅晶体晶界 EBIC_100 K 晶粒大小：1－10mm 晶界垂直于表面 没有污染的晶界 晶界负面作用很小 SE, EBSD, and EBIC images of GBs in mc-Si with different Fe contamination levels. The contamination level was light (800oC), moderate (900-1000oC), or heavy (1100oC). ?3*- ?3{112}. ?3 ?3 ?3 ?9 ?27 ?27 ?3 ?3 ?3* ?3 R R R ?3 ?3* ?3 ?3 ?3 ?27 ?9 R Lightly contaminated ?9 ?3 ?3 ?27 R R R Denuded zone Moderately contaminated #1 Moderately contaminated #2 Heavily contamin