热丝CVD法沉积固态扩散源制备晶硅太阳电池p~+/n~+发射极研究
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摘要
为进一步提高晶硅太阳能电池发射极的性能,本文提出了一种新的发射极制备技术-低温CVD法沉积固态薄膜扩散源并进行高温扩散。采用热丝化学气相沉积法(HWCVD)在单晶硅片上沉积重掺杂硅基薄膜作为固态扩散源,然后在空气氛围下的管式炉中进行高温扩散,最后用稀HF溶液去除表面的BSG/PSG。通过掺磷薄膜扩散在P型单晶硅片上制备了方阻在50~250Ω/□范围内可控的n+型发射极;通过掺硼薄膜扩散在N型硅片上制备了方阻在150~600Ω/□范围内可控的p+型发射极。并且通过在源气体中加入CO2作为氧源,实现了扩散后硅片表面残留扩散源层的彻底去除。
A novel solid-phase diffusion method is mentioned in this paper to make the emitters of the crystalline silicon solar cells.The solid diffusion source films are heavily doped amorphous silicon-based films deposited by Hot Wire Chemical-vapor Deposition(HWCVD) at low substrate temperature.The films are doped by B_2H_6 for p-type and PH_3 for n-type.After the films deposition,the wafers are thermaltreated in a tube furnace at air atmosphere.The Borosilicate glass(BSG) and Phosphorus silicon glass(PSG) are removed by diluted HF solution.With phosphorous source diffusion,the sheet resistance of n+emitter in the range of 50-250 Ω/□ is achieved on p-type monocrystalline silicon wafer.The sheet resistance of p+emitter in the range of 150-600 Ω/□ is achieved on n-type monocrystalline silicon.CO_2 as oxygen source added to the precursor gases during the deposition process by HWCVD is succeeded to thoroughly remove the source layer after diffusion.
A novel solid-phase diffusion method is mentioned in this paper to make the emitters of the crystalline silicon solar cells.The solid diffusion source films are heavily doped amorphous silicon-based films deposited by Hot Wire Chemical-vapor Deposition(HWCVD) at low substrate temperature.The films are doped by B_2H_6 for p-type and PH_3 for n-type.After the films deposition,the wafers are thermaltreated in a tube furnace at air atmosphere.The Borosilicate glass(BSG) and Phosphorus silicon glass(PSG) are removed by diluted HF solution.With phosphorous source diffusion,the sheet resistance of n+emitter in the range of 50-250 Ω/□ is achieved on p-type monocrystalline silicon wafer.The sheet resistance of p+emitter in the range of 150-600 Ω/□ is achieved on n-type monocrystalline silicon.CO_2 as oxygen source added to the precursor gases during the deposition process by HWCVD is succeeded to thoroughly remove the source layer after diffusion.
引文
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[13]Duygulu O,Duygulu N,Iskender I,et al.Study of the a-Si:H/c-Si Heterointerface by Ex-Situ Spectroscopic Ellipsometry,Infrared Spectroscopy,and Solar Cell Modeling[J].Chinese Journal of Physics,2015,53(3):147-150.
[2]Kerr M J,Schmidt J,Cuevas A,et al.Surface Recombination Velocity of Phosphorus-diffused Silicon Solar Cell Emitters Passivated with PlasmaEnhanced Chemical Vapor Deposited Silicon Nitride and Thermal Silicon Oxide[J].Journal of Applied Physics,2001,89(7):3821-3826.
[3]Green M A.The Path to 25%Silicon Solar Cell Efficiency:History of Silicon Cell Evolution[J].Progress in Photovoltaics Research&Applications,2009,17(3):183-189.
[4]Masuko K,Shigematsu M,Hashiguchi T,et al.Achievement of More than 25%Conversion Efficiency with Crystalline Silicon Heterojunction Solar Cell[J].IEEE Journal of Photovoltaics,2014,4(6):1433-1435.
[5]Smith D D,Cousins P,Westerberg S,et al.Toward the Practical Limits of Silicon Solar Cells[J].IEEE Journal of Photovoltaics,2014,6(4):1465-1469.
[6]Wang Z,Han P,Lu H,et al.Advanced PERC and PERL Production Cells with 20.3%Record Efficiency for Standard Commercial p‐type Silicon Wafers[J].Progress in Photovoltaics:Research and Applications,2012,20(3):260-268.
[7]Kerr M J,Schmidt J,Cuevas A,et al.Surface Recombination Velocity of Phosphorus-diffused Silicon Solar Cell Emitters Passivated with Plasma Enhanced Chemical Vapor Deposited Silicon Nitride and Thermal Silicon Oxide[J].Journal of Applied Physics,2001,89(7):3821-3826.
[8]Zhao J,Wang A,Green M A.24%Efficient PERL Structure Silicon Solar Cells[C]//Photovoltaic Specialists Conference,1990,Conference Record of the Twenty First IEEE.IEEE,1990:333-335.
[9]Dastgheib-Shirazi A,Steyer M,Micard G,et al.Relationships between Diffusion Parameters and Phosphorus Precipitation during the POCl3Diffusion Process[J].Energy Procedia,2013,38:254-262.
[10]Suenaga K,Colliex C,Demoncy N,et al.Synthesis of Nanoparticles and Nanotubes with Well-separated Layers of Boron Nitride and Carbon[J].Science,1997,278(5338):653-655.
[11]Wang Q.Hot-wire CVD Amorphous Si Materials for Solar Cell Application[J].Thin Solid Films,2009,517(12):3570-3574.
[12]张磊,沈鸿烈,黄海宾,等.热丝CVD法低温制备的多晶硅薄膜质量对衬底依赖性的研究[J].功能材料,2011,42(11):1947-1950.
[13]Duygulu O,Duygulu N,Iskender I,et al.Study of the a-Si:H/c-Si Heterointerface by Ex-Situ Spectroscopic Ellipsometry,Infrared Spectroscopy,and Solar Cell Modeling[J].Chinese Journal of Physics,2015,53(3):147-150.