Preparation and Characterization of Boron-Doped p-type a-Si:H Thin Film

doi:10.7517/j.issn.1674-0475.2010.04.296

Abstract

Abstract: The boron-doped amorphous silicon(a-Si:H)thin film was deposited on glass substrate by plasma enhanced chemical vapor deposition(PECVD).SiH₄ and B₂H₆ with high hydrogen dilution are used as the reactive gas and dopant gas,respectively.The transmission spectra and the reflection spectra of the films were measured by NKD thin film analysis system,the refractive index,extinction coefficient,absorption coefficient and other optical parameters of the films were fitted out and optical band gap of the samples were calculated using Tauc method.The results have shown that with the dopant increase,the refractive index of amorphous silicon thin film decreases as the light wavelength increases,and the refractive index at 500 nm wavelength was more than 4.3;and the absorption coefficient was as high as 1.5×10⁵ cm^-1 at 500 nm wavelength.Optical band gap of boron-doped amorphous silicon(a-Si:H)thin film ranges from 1.7 to 1.8 eV.In a word,it is necessary to reduce the dopant concentration to get the widow layer with low absorption.

Key words: RF-PECVD, amorphous silicon thin film, refractive, extinction coefficient, absorption coefficient, optical bandgap

CLC Number:

O484

XIA Dong-lin, WANG Hui-fang, SHI Zheng-zhong, ZHANG Xing-liang, LIU Jun. Preparation and Characterization of Boron-Doped p-type a-Si:H Thin Film[J]. Imaging Science and Photochemistry, 2010, 28(4): 296-304.

References

[1] Spear WE,Lecomber P G.Substitutional doping of amorphous silicon[J].Solid State Communication,1975,17(9):1193-1196.
[2] 余云鹏,林舜辉,林璇英,等.非晶硅薄膜厚度均匀性对其透射光谱的影响[J].汕头大学学报,2004,19(1):50-54.Yu Y P,Lin S H,Lin X Y,et al.Effect of thickness homogeneity on optical transmittance spectra of a-Si:Hfil ms[J].Journal of Shantou University,2004,19(1):50-54.
[3] 韩大星,王万录,张智.非晶硅电致发光机理及用电致发光谱研究太阳能电池本征层中的缺陷态能量分布[J].物理学报,1999,48(8):1484-1490.Han D X,Wang WL,Zhang Z.Mechanismof electroluminescence froma-Si:Hand studies of defect energy dis-tributioninintrinsic layer of a-Si:Hsolar cells by electroluminescence spectra[J].Chinese Physics,1999,48(8):1484-1490.
[4] 朱嘉琦,卢佳,田桂,等.非晶硅太阳电池窗口层材料掺硼非晶金刚石的研究[J].无机材料学报,2008,23(5):1064-1066Zhu J Q,Lu J,Tian G,et al.Using boron doped amorphous diamond fil ms as windowlayer of amorphous siliconsolar cells.Journal of Inorganic Materials,2008,23(5):1064-1066.
[5] 倪牮,张建军,王先宝,等.低温高速率沉积非晶硅薄膜及太阳电池[J].光电子.激光,2010,21(2):217-221.Ni J,Zang J J,Wang X B,et al.Lowtemperature and high deposition rate fabricating a-Si:Hthinfil ms and solarcells[J].Journal of Optoelectronics.Laser,2010,21(2):217-221.
[6] Platz R,Wagner S,Hof C,et al.Influence of excitation frequency,temperature,and hydrogen dilution on thestability of plasma enhanced chemical vapor deposited a-Si:H[J].J.Appl.Phys.,1998,84(7):3949-3953.
[7] Hishikawa Y,Tsuda S,Nakamura N,et al.Device-quality wide-gap hydrogenated amorphous siliconfil ms deposi-ted by plasma chemical vapor deposition at lowsubstrate temperatures[J].J.Appl.Phys.,1991,69(1):508-510.
[8] Chen G H,Hu X H,Yin S Y,et al.I mprovement onthe conventional MWECR-CVDsystemand preparation ofhydrogenated amorphous silicon fil ms[J].Vacuum,2005,77(3):355-358.
[9] Goncalves C,Charvet S,Zeinert A,et al.Nanocrystalline silicon thinfil ms prepared by radiofrequency magnetronsputtering[J].Thin Solid Fil ms,2002,403?404:91-96.
[10] 罗士雨,冯磊,汪洪,等.非晶硅薄膜制备及其晶化特性研究[J].人工晶体学报,2008,37(5):1191-1194.Luo S Y,Feng L,Wang H,et al.Study onthe preparation of amorphous siliconfil mandits crystallization prop-erty[J].Journal of Synthetic Crystals,2008,37(5):1191-1194.
[11] Tarui H,Kishi Y,Nakamura N,et al.On P layers for high efficiency amorphous silicon solar cells[J].SolarEnergy Materials,1991,23(2-4):227-238.
[12] Tao K,Zhang D X,Zhao J F,et al.Lowtemperature deposition of boron-doped microcrystalline Si:Hthinfil mandits applicationin silicon based thin fil msolar cells[J].Journal of Non-Crystalline Solids,2010,356(6-8):299-303.
[13] 钱祥忠.硼轻掺杂对非晶硅薄膜光电性能的影响[J].光电子技术,2004,24(2):93-95.Qian X Z.Influence of light-dope boron on optoelectronic properties of a-Si fil ms[J].Optoelectronic Technolo-gy,2004,24(2):93-95.
[14] Chattopadhyay S,Das D.Efficient boronincorporationin hydrogenated amorphous siliconfil ms by a novel com-bination of rf glow discharge technique and heated filament[J].Jpn.J.Appl.Phys.,1995,34(10):5743-5748.
[15] Fedders P A,Drabold D A.Si mulation of boron doping in a-Si:H[J].Journal of Non-Crystalline Solids,1998,227-230:376-379.
[16] 何宇亮,陈光华,张仿清.非晶态半导体物理学[M].北京:高等教育出版社,1989.284-292.He Y L,Chen G H,Zhang F Q.Amorphous Semiconductor Physics[M].Beijing:Higher Education Press,1989.284-292.
[17] 汪昌州,杨仕娥,卢景霄.硅基薄膜太阳电池窗口材料的研究进展[J].材料导报,2007,27(2):14-17.Wang C Z,Yang S E,Lu J X.Progress in research on window materials of silicon fil msolar cells[J].MaterialsReview,2007,27(2):14-17.
[18] Veneri P D,Mercaldo L V,Minarini C,et al.VHF-PECVD microcrystalline silicon:from material to solar cells[[J].Thin Solid Fil ms,2004,451-452:269-273.
[19] Yamasaki S,Matsuda A,Tanaka K.Anomalous optical and structural properties of B-doped a-Si:H[J].Jpn.J.Appl.Phys.,1982,21(12):789-791.