氢化非晶氧化硅(α-SiOx∶H)是一种优质的硅片表面钝化材料.采用PECVD法,以 SiH4、CO2和 H 2作为气源制备α-Si O x∶H 薄膜钝化 Cz-Si 表面,研究了沉积气压和CO2∶SiH4流量比对钝化效果的影响规律及作用机制.采用准稳态光电导法测试了硅片的有效少子寿命并依此计算出其表面复合速率以对薄膜的钝化效果进行定量表征,采用光谱型椭偏仪测试了样品的介电常数虚部ε2谱对样品微观结构进行了定性分析.结果表明,(1)在所研究范围内,氧掺入非晶硅薄膜使得薄膜结构趋向非晶化,沉积气压主要对薄膜中的空位浓度造成影响,而 CO2/SiH4流量比的增加可增加薄膜中的 H 含量并改变了硅氢键的结构,从而影响薄膜的钝化效果；(2)在 CO2/SiH4流量比为3．0/3．0 mL/min,沉积气压为22 Pa 条件下获得了最优钝化效果,钝化后硅片有效少子寿命为975μs,表面复合速率为3．9 cm/s.
Amorphous hydrogenated silicon sub-oxide (α-SiOx∶H)is an excellent passivation material for sili-con wafer.In this paper,theα-SiOx∶H films were deposited to passivate n-type Cz-Si wafer by PECVD meth-od,SiH4 ,CO2 and H2 were used as precursors.The deposition pressure and the ratio of the CO2/SiH4 flow rate (RCO2/SiH4 )were optimized and their operation mechanisms on the passivation effect were analyzed.Quasi-steady state photoconductance method and spectroscopic ellipsometer were used to test the effective lifetime and imagi-nary part of the dielectric function (ε2 )of the passivated wafers.It was found that:(1)In this study,the doped oxygen in the films makes them amorphized.The operation mechanisms on the passivation effect of the two pa-rameters were different.Generally,the deposition pressure affects the void fraction in the films and RCO2/SiH4 af-fects the hydrogen fraction and structure.(2)The highest effective lifetime 975μs and the lowest surface re-combination 3.9 cm/s were gotten when RCO2/SiH4 was 3.0/3.0 mL/min and the deposition pressure was 22 Pa.
参考文献
| [1] | Jik Lee, S.;Hwan Kim, S.;Won Kim, D.;Hyung Kim, K.;Kyu Kim, B.;Jang, J. .Effect of hydrogen plasma passivation on performance of HIT solar cells[J].Solar Energy Materials and Solar Cells: An International Journal Devoted to Photovoltaic, Photothermal, and Photochemical Solar Energy Conversion,2011(1):81-83. |
| [2] | Martin I;Vetter M;Qorpella A et al.Surface passiva-tion of p-type crystalline Si by plasma enhanced chemical vapor deposited amorphous SiCx:H films[J].Applied Physics Letters,2001,79:2199. |
| [3] | Thomas Mueller;Stefan Schwertheim;Wolfgang R. Fahrner .Crystalline silicon surface passivation by high-frequency plasma-enhanced chemical-vapor-deposited nanocomposite silicon suboxides for solar cell applications[J].Journal of Applied Physics,2010(1):014504-1-014504-11. |
| [4] | Jia Guangzhi,Liu Honggang,Chang Hudong.Annealing optimization of hydrogenated amorphous silicon suboxide film for solar cell application[J].半导体学报,2011(05):7-9. |
| [5] | Lauinger T;Schmidt J;Aberle A G et al.Record low surface recombination velocities on 1 cm p-silicon using remote plasma silicon nitride passivation annealing opti-mization of hydrogenated amorphous silicon suboxide film for solar cell application[J].Applied Physics Letters,1996,68:1232. |
| [6] | Descoeudres A;Barraud L;Bartlome R et al.The silane depletion fraction as an indicator for the amorphous/crys-talline silicon interface passivation quality[J].Applied Physics Letters,2010,97:183505. |
| [7] | Zhao, L;Diao, HW;Zeng, XB;Zhou, CL;Li, HL;Wang, WJ .Comparative study of the surface passivation on crystalline silicon by silicon thin films with different structures[J].Physica, B. Condensed Matter,2010(1):61-64. |
| [8] | Ji K;Choi J;Yang H et al.A study of crystallinity in amorphous Si thin film for silicon heteroj unction solar cell[J].Solar Energy Materials and Solar Cells,2011,95:203-206. |
| [9] | Mueller T;Schwerthelm J S;Fahmer W R.Application of wide bandgap hydrogenated amorphous silicon oxide layers to heteroj unction solar cells for high quality passi-vation[M].San Diego:IEEE,2008:1-6. |
| [10] | 张东华;周浪;黄海宾.PECVD法沉积α-SiOx:H层钝化 N-型晶体硅表面的研究[A].北京,2012 |
| [11] | Morral A F;Cabarrocas P R .Structure and hydrogen content of polymorphous silicon thin films studied by spectroscopic ellipsometry and nuclear measurements[J].Physical Review B,2004,69:125307. |
| [12] | Levi D;Iwaniczko E;Page M.Silicon heterojunc-tion solar cell characterization and optimization using in situ and Ex situ spectroscopic ellipsometry[A].Ha-waii,2006 |
| [13] | Ge J;Ling Z P;Wong J et al.Optimisation of intrinsic a-Si:H passivation layers in crystalline-amorphous sili-con heteroj unction solar cells[J].Energy Procedia,2012,15:107-117. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%