楊德仁-鑄造多晶硅的缺陷

1、鑄造多晶硅的缺陷鑄造多晶硅的缺陷 楊楊 德德 仁仁浙江大學硅材料國家重點實驗室 Muticrystalline Silicon 雜質雜質 缺陷缺陷 間隙氧 替位碳 過渡金屬雜質（Fe、Cu、Ni、Cr） 微缺陷 位錯 晶界影響電池效率影響電池效率!硅晶體的雜質和缺陷硅晶體的雜質和缺陷氧在硅熔體中的傳遞示意圖Raw materialsQuartz crucibles2222S iOS iS iOS iO部 分硅晶體中的氧硅晶體中的氧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：氧擴散模型氧擴散模型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)硅晶體中的金屬雜質硅晶體中的金屬雜質 Lifetime distribution of minor carriers磷吸雜磷吸雜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.硅晶體位錯硅晶體位錯硅晶體晶界硅晶體晶界EBIC_100 Kl晶粒大?。壕Я４笮。?10mml晶界垂直于表面晶界垂直于表面l沒有污染的晶界沒有污染的晶界晶界負面作用很小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; (