杨德仁-铸造多晶硅的缺陷

1、铸造多晶硅的缺陷铸造多晶硅的缺陷 杨杨 德德 仁仁浙江大学硅材料国家重点实验室 Muticrystalline Silicon 杂质杂质 缺陷缺陷 间隙氧 替位碳 过渡金属杂质（Fe、Cu、Ni、Cr） 微缺陷 位错 晶界影响电池效率影响电池效率!硅晶体的杂质和缺陷硅晶体的杂质和缺陷氧在硅熔体中的传递示意图Raw materialsQuartz crucibles2222S iOS iS iOS iO部 分硅晶体中的氧硅晶体中的氧Solar Energy Material and Solar Cells, Vol.62, 37(2000). Oxygen clustersSolid State

2、 Phenomena, Vol. 82, 2002, P.707-712 0.00.20.40.60.81.002468 Oi ( X 1017cm-3)Fraction of the ingot (g) Pfanns law ExperimentalExperimental Oi profile in growth direction and simulated Oi profile according to Pfanns law (segregation coefficient 1.25). S i(m elt) + O (m elt) = S iO (gas)gsgA ()gpDJpp

3、Diffusion from melt to surfaceDiffusion from melt to surfaceLALLDJLSC C（CL、CS is oxygen concentration in melt and solid near interface, respectively） Reaction in the surface of meltReaction in the surface of melt；（PS、PP is equilibrium pressure of SiO in the surface and the pressure in furnaceEvapora

4、tion of SiO from surfaceFlux of oxygen LSe ffLvKCL GL GLL GL GLKCCKC()LLL SL SL GL GdV CAAdt 101DLKeffvLGseffCKCg（01XseffCKCgA=AL-S=AL-G ；CL=CS/Keff：氧扩散模型氧扩散模型0.00.20.40.60.81.002468 Oi (X1017cm-3)Fraction of the ingot (g) Simulated ExperimentalExperimental Oi profile in growth direction and simulat

5、ed Oi profile on the basis of our model. 0.00.20.40.60.81.002468X2=3.0 Oi (X 1017cm-3)Fraction of the ingot (g)X1=1.45X3=6.0X3X2X1Simulated Oi profile as a function of the exponent X. Solar Energy Material and Solar Cells, (2007), in print4006008001000 12002468 McA McB CzOxygen concentration (1017 c

6、m-3)Temperature (oC)Interstitial oxygen concentrations of samples annealed for 24 h vs. annealing temperature.Solar Energy Materials and Solar Cells, Vol.72, 541(2002)05101520250246810 Cz-Si mc-SiOxygen conc. (x1017cm-3)Annealing Time (hour)Oxygen conc of the annealed mc-B and Cz samples051015202502

7、46810 Cz mcOxygen conc. (x1017cm-3)Annealing Time (hour)1150C950CFTIR 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硅晶体中的金属杂质 Lifetime distribution of minor carriers磷吸杂磷吸杂012340369As grownPocl3 gettered Average lifetime( s)Ingot posit

8、ion from the bottom (cm)Region 1Region 202468Effective lifetime(s) Before RTP After RTPcMinority 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

9、 900.硅晶体位错硅晶体位错硅晶体晶界硅晶体晶界EBIC_100 Kl晶粒大小：晶粒大小：110mml晶界垂直于表面晶界垂直于表面l没有污染的晶界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 w i t h d i f f e r e n t F e contamination levels. The contamination level was light (800C), moderate (900-1000C), or heavy (1100C). 3*- 3112.33392727333*3RRR33*333279R

10、Lightlycontaminated93327RRRDenuded zoneModeratelycontaminated #1Moderatelycontaminated #2Heavilycontaminated(a)(b)(c)(d)SEEBIC_300 KEBIC_100 KEBSD200m200m200m100mEBSD images of the large-angle GBs in the mc-Si cut from top, central, and bottom positions. The GB characters were denoted by or R (rando

11、m GBs). 300 and 100 K EBIC images of the GBs in the as-grown and H-passivated contamination-free mc-Si (cut from the central position). Small-angle GBs were denoted SA.300 and 100 K EBIC images of the GBs in the as-grown and H-passivated contaminated mc-Si (cut from the top or bottom positions).Stat

12、istic diagram regarding the 300 and 100 K EBIC contrast of the GBs in the as-grown and H-passivated contamination-free and contaminated mc-Si. The decrease in the EBIC contrast of the GBs after H-passivation was also illustrated.(a) Contamination-free mc-Si_300 K; (c) Contaminated mc-Si_300 K; (b) Contamination-free mc-Si_100 K; (