SEMICONDUCTOR TECHNOLOGY

Disordered wall arrays by photo-assisted electrochemical etching in n-type silicon

Yaohu Lei, Zhigang Zhao, Jinchuan Guo, Ji Li and Hanben Niu

+ Author Affiliations

 Corresponding author: Li Ji, Email: liji@szu.edu.cn; Niu Hanben, Email: hbniu@szu.edu.cn

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Abstract: The fabrication of ordered, high aspect-ratio microstructures in silicon by use of photo-assisted electrochemical etching is an important technology, where voltage and current density are significant factors. In this paper, disordered walls appear in 5-inch n-type silicon wafers when a large current density is used. Based on the theory of space charge region, these disordered walls are caused by the contradiction between the protection from dissolution by a high applied voltage and the dissolution by a high current density. To verify this point, wall arrays were fabricated at different applied voltages and current densities. Moreover, the critical voltage was kept constant and different current densities were applied to obtain conditions for avoiding disordered walls and achieving uniform wall arrays. Finally, a wall array with a period of 5.6μm and a depth of 55μm was achieved at an applied voltage of 3 V and a monotonically increasing current density ranging from 22.9 to 24.5 mA/cm2.

Key words: electrochemical etchingwall arrayhigh aspect-ratiosilicondisordered wall



[1]
González E Q, Wusu E O, Carstensen J, et al. How to make optimized arrays of Si wires suitable as superior anode for Li-ion batteries. J Electrochem Soc, 2011, 158(11): E119 doi: 10.1149/2.069111jes
[2]
Lei Y H, Liu X, Guo J C, et al. Development of X-ray scintillator functioning also as an analyser grating used in grating-based X-ray differential phase contrast imaging. Chin Phys B, 2011, 20(4): 042901 doi: 10.1088/1674-1056/20/4/042901
[3]
Chen X, Lin J, Yuan D, et al. Obtaining of high area-ratio free standing silicon microchannel plate via modified electrochemical procedure. J Micromech Microeng, 2008, 18(3): 037003 doi: 10.1088/0960-1317/18/3/037003
[4]
Kraeh C, Popsecu A, Schieber M, et al. Fabrication of high aspect ratio microtube arrays for 2D photonic crystals. Mater Res Express, 2014, 1: 026201 doi: 10.1088/2053-1591/1/2/026201
[5]
Peng Bobo, Wang Fei, Liu Tao, et al. Novel method of separating macroporous arrays from p-type silicon substrate. Journal of Semiconductors, 2012, 33(4): 043004 doi: 10.1088/1674-4926/33/4/043004
[6]
Ottow S, Lehmann V, Föll H. Development of three-dimensional microstructure processing using macroporous n-type silicon. Appl Phys A, 1996, 63:153 http://www.researchgate.net/publication/225670039_Development_of_three-dimensional_microstructure_processing_using_macroporous_n-type_silicon
[7]
Bassu M, Surdo S, Strambini L M, et al. Electrochemical micromachining as an enabling technology for advanced silicon microstructure. Adv Funct Mater, 2012, 22: 1222 doi: 10.1002/adfm.v22.6
[8]
Astrova E V, Fedulova G V. Formation of deep periodic trenches in photo-electrochemical etching of n-type silicon. J Micromech Microeng, 2009, 19: 095009 doi: 10.1088/0960-1317/19/9/095009
[9]
Lei Y H, Guo J C, Zhao Z G, et al. Study of deep etching in silicon by photo-assisted electrochemical technique. Semiconductor Technology, 2010, 35(6): 517 (in Chinese)
[10]
Lehmann V. The physics of macropore formation in low doped n-type silicon. J Electrochem Soc, 1993, 140(10): 2836 doi: 10.1149/1.2220919
[11]
Wang G, Fu S, Chen L, et al. Influence of voltage on photo-electrochemical etching of n-type macroporous silicon arrays. Journal of Semiconductors, 2010, 31(11): 116002 doi: 10.1088/1674-4926/31/11/116002
[12]
Wang G, Chen L, Qin X, et al. Influence of etching current density on the morphology of macroporous silicon arrays by photo-electrochemical etching. Journal of Semiconductors, 2010, 31(7): 074011 doi: 10.1088/1674-4926/31/7/074011
[13]
Lin J C, Lai C M, Jehng W D, et al. Effect of ethanol on the photoelectrochemical fabrication of macroporous n-Si (100) in HF solution. J Electrochem Soc, 2008, 155(6): D436 doi: 10.1149/1.2898687
[14]
Zhao Z, Guo J, Lei Y, et al. Photoelectrochemical etching of uniform macropore array on full 5-inch silicon wafers. Journal of Semiconductors, 2010, 31(7): 076001 doi: 10.1088/1674-4926/31/7/076001
[15]
Zhang X G. Mechanism of pore formation on n-type silicon. J Electrochem Soc, 1991, 138(12): 3750 doi: 10.1149/1.2085494
[16]
Föll H, Christophersen M, Carstensen J, et al. Formation and application of porous silicon. Mater Sci Eng R, 2002, 39: 93 doi: 10.1016/S0927-796X(02)00090-6
[17]
Geppert T, Schweizer S L, Gösele U, et al. Deep trench etching in macroporous silicon. Appl Phys A, 2006, 84: 237 doi: 10.1007/s00339-006-3628-7
Fig. 1.  Prestructuring process for both sides of the silicon wafer.

Fig. 2.  Wall arrays obtained at (a) 3 V, 22.9 mA/cm2 and (b) 3 V, 22.9–27.8 mA/cm2.

Fig. 3.  Schematic diagram of etching results under the different conditions: (a) critical voltage and current density, (b) critical voltage and large current density, (c) large voltage and critical current density, (d) large voltage and large current density.

Fig. 4.  SEM side views (a) to (d) corresponding to samples #1-#4.

Fig. 5.  Disordered walls at a voltage of 3 V with current density varying from 18.9 to 29 mA/cm2.

Fig. 6.  Wall arrays fabricated at the critical voltage with a monotonically increasing current density ranging from 22.9 to 24.5 mA/cm2.

Table 1.   Etching conditions and results.

[1]
González E Q, Wusu E O, Carstensen J, et al. How to make optimized arrays of Si wires suitable as superior anode for Li-ion batteries. J Electrochem Soc, 2011, 158(11): E119 doi: 10.1149/2.069111jes
[2]
Lei Y H, Liu X, Guo J C, et al. Development of X-ray scintillator functioning also as an analyser grating used in grating-based X-ray differential phase contrast imaging. Chin Phys B, 2011, 20(4): 042901 doi: 10.1088/1674-1056/20/4/042901
[3]
Chen X, Lin J, Yuan D, et al. Obtaining of high area-ratio free standing silicon microchannel plate via modified electrochemical procedure. J Micromech Microeng, 2008, 18(3): 037003 doi: 10.1088/0960-1317/18/3/037003
[4]
Kraeh C, Popsecu A, Schieber M, et al. Fabrication of high aspect ratio microtube arrays for 2D photonic crystals. Mater Res Express, 2014, 1: 026201 doi: 10.1088/2053-1591/1/2/026201
[5]
Peng Bobo, Wang Fei, Liu Tao, et al. Novel method of separating macroporous arrays from p-type silicon substrate. Journal of Semiconductors, 2012, 33(4): 043004 doi: 10.1088/1674-4926/33/4/043004
[6]
Ottow S, Lehmann V, Föll H. Development of three-dimensional microstructure processing using macroporous n-type silicon. Appl Phys A, 1996, 63:153 http://www.researchgate.net/publication/225670039_Development_of_three-dimensional_microstructure_processing_using_macroporous_n-type_silicon
[7]
Bassu M, Surdo S, Strambini L M, et al. Electrochemical micromachining as an enabling technology for advanced silicon microstructure. Adv Funct Mater, 2012, 22: 1222 doi: 10.1002/adfm.v22.6
[8]
Astrova E V, Fedulova G V. Formation of deep periodic trenches in photo-electrochemical etching of n-type silicon. J Micromech Microeng, 2009, 19: 095009 doi: 10.1088/0960-1317/19/9/095009
[9]
Lei Y H, Guo J C, Zhao Z G, et al. Study of deep etching in silicon by photo-assisted electrochemical technique. Semiconductor Technology, 2010, 35(6): 517 (in Chinese)
[10]
Lehmann V. The physics of macropore formation in low doped n-type silicon. J Electrochem Soc, 1993, 140(10): 2836 doi: 10.1149/1.2220919
[11]
Wang G, Fu S, Chen L, et al. Influence of voltage on photo-electrochemical etching of n-type macroporous silicon arrays. Journal of Semiconductors, 2010, 31(11): 116002 doi: 10.1088/1674-4926/31/11/116002
[12]
Wang G, Chen L, Qin X, et al. Influence of etching current density on the morphology of macroporous silicon arrays by photo-electrochemical etching. Journal of Semiconductors, 2010, 31(7): 074011 doi: 10.1088/1674-4926/31/7/074011
[13]
Lin J C, Lai C M, Jehng W D, et al. Effect of ethanol on the photoelectrochemical fabrication of macroporous n-Si (100) in HF solution. J Electrochem Soc, 2008, 155(6): D436 doi: 10.1149/1.2898687
[14]
Zhao Z, Guo J, Lei Y, et al. Photoelectrochemical etching of uniform macropore array on full 5-inch silicon wafers. Journal of Semiconductors, 2010, 31(7): 076001 doi: 10.1088/1674-4926/31/7/076001
[15]
Zhang X G. Mechanism of pore formation on n-type silicon. J Electrochem Soc, 1991, 138(12): 3750 doi: 10.1149/1.2085494
[16]
Föll H, Christophersen M, Carstensen J, et al. Formation and application of porous silicon. Mater Sci Eng R, 2002, 39: 93 doi: 10.1016/S0927-796X(02)00090-6
[17]
Geppert T, Schweizer S L, Gösele U, et al. Deep trench etching in macroporous silicon. Appl Phys A, 2006, 84: 237 doi: 10.1007/s00339-006-3628-7
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    Received: 21 December 2015 Revised: 03 March 2016 Online: Published: 01 October 2016

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      Yaohu Lei, Zhigang Zhao, Jinchuan Guo, Ji Li, Hanben Niu. Disordered wall arrays by photo-assisted electrochemical etching in n-type silicon[J]. Journal of Semiconductors, 2016, 37(10): 106001. doi: 10.1088/1674-4926/37/10/106001 Y H Lei, Z G Zhao, J C Guo, J Li, H B Niu. Disordered wall arrays by photo-assisted electrochemical etching in n-type silicon[J]. J. Semicond., 2016, 37(10): 106001. doi: 10.1088/1674-4926/37/10/106001.Export: BibTex EndNote
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      Yaohu Lei, Zhigang Zhao, Jinchuan Guo, Ji Li, Hanben Niu. Disordered wall arrays by photo-assisted electrochemical etching in n-type silicon[J]. Journal of Semiconductors, 2016, 37(10): 106001. doi: 10.1088/1674-4926/37/10/106001

      Y H Lei, Z G Zhao, J C Guo, J Li, H B Niu. Disordered wall arrays by photo-assisted electrochemical etching in n-type silicon[J]. J. Semicond., 2016, 37(10): 106001. doi: 10.1088/1674-4926/37/10/106001.
      Export: BibTex EndNote

      Disordered wall arrays by photo-assisted electrochemical etching in n-type silicon

      doi: 10.1088/1674-4926/37/10/106001
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      Project supported by the National Special Foundation of China for Major Science Instrument (No.61227802), the National Natural Science Foundation of China (No.61405120), the National Program on Key Basic Research Project (No.2012CB825802), and the China Postdoctoral Science Foundation (No.2014M552224)

      National Special Foundation of China for Major Science Instrument 61227802

      National Natural Science Foundation of China 61405120

      China Postdoctoral Science Foundation 2014M552224

      National Program on Key Basic Research Project 2012CB825802

      More Information
      • Corresponding author: Li Ji, Email: liji@szu.edu.cn; Niu Hanben, Email: hbniu@szu.edu.cn
      • Received Date: 2015-12-21
      • Revised Date: 2016-03-03
      • Published Date: 2016-10-01

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