Thin Film Thickness and Uniformity Measurement for Lab-on-Chip Based Nanoelectrode Biosensor Development

Abstract:

One of the advantages of silicon substrate over other semiconductor substrate is the high temperature process capability of the silicon. In this work, silicon wafer is used for thermal processing which involves many high temperature processes such as oxidation and deposition. Thin films on the wafer surface are investigated for its thickness and uniformity. Silicon dioxide (SiO₂) is initially grown using wet oxidation method and characterized for its thickness using FilmetricsSpectrometer. The thickness of SiO₂ achieved is less than 300nm. Silicon Nitride (Si₃N₄) is then deposited by sputter method and its thickness is measured at 210 nm. For the electrode, polysilicon (PolySi) is deposited using Low Pressure Chemical Vapor Deposition (LPCVD) process. Silane (SiH₄) is used as the source forPolySi deposition and the thickness is measured at 160nm. Standard deviation is calculated based on the layer thickness and the uniformity is checked across 5 points on the wafer. Hence, it is very important to have a uniform layer across the wafer surface for a defect free device and at the same time it protects the sensitivity of the sensor.

• Periodical: Advanced Materials Research (Volume 832)
• Pages: 95-100
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.832.95
• Online since: November 2013
• Authors: Balakrishnan Sharma Rao, Uda Hashim, Tijjani Adam
• Keywords: Filmetrics Spectrometer, LPCVD, Oxidation, Spectral Reflectance, Thin Film

References

[1] B. S. Rao, U. Hashim, T. Dhahi, and T. Adam, "DI Water Electrical Characteristics Monitoring Using in House Fabricated Polysilicon Nanoelectrode Based Transducer," International Journal of Enhanced Research in Science Technology & Engineering, vol. 1, no. 1, p.1–6, 2012.

DOI: 10.1109/iecbes.2012.6498063

[2] A. S. Charlene, G. Elias, and R. Miguel, "Chemical Warfare Agents: Biosensors for Detection," Dekker Encyclopedia of Nanoscience and Nanotechnology, Second Edition, p.842–855, 2009.

DOI: 10.1201/noe0849396397.ch74

[3] Y. Umasankar, S. A. Kumar, and S. M. Chen, Nanostructured Materials for Electrochemical Biosensors. Nova Science Publishers, 2009.

[4] U. Hashim, S. F. A. Rahman, M. N. M. Nor, and S. Salleh, "Design and process development of silicon nanowire based DNA biosensor using electron beam lithography," 2008 International Conference on Electronic Design, p.1–6, Dec. 2008.

DOI: 10.1109/iced.2008.4786648

[5] U. Hashim, K. A. Rahman, and A. R. A. J. Abdullah, "Mask design and fabrication of LiSFET for Light Sensor application," 2008 International Conference on Electronic Design, p.1–5, Dec. 2008.

DOI: 10.1109/iced.2008.4786651

[6] T. S. Dhahi, U. Hashim, M. E. Ali, and T. Nazwa, "Fabrication of Amorphous Silicon Microgap Structure for Energy Saving Devices," Sains Malaysiana, vol. 41, no. 6, p.755–759, 2012.

[7] J. Tallal, D. Peyrade, F. Lazzarino, K. Berton, C. Perret, M. Gordon, C. Gourgon, and P. Schiavone, "Replication of sub-40nm gap nanoelectrodes over an 8-in. substrate by nanoimprint lithography," Microelectronic Engineering, vol. 78–79, p.676–681, Mar. 2005.

DOI: 10.1016/j.mee.2004.12.084

[8] H. Geng, Semiconductor Manufacturing Handbook. McGraw-Hill Education, 2005.

[9] T. S. Dhahi, U. Hashim, M. E. Ali, N. M. Ahmed, and T. Nazwa, "Fabrication of Lateral Polysilicon Gap of Less than 50 nm Using Conventional Lithography," Journal of Nanomaterials, vol. 2011, p.1–8, 2011.

DOI: 10.1155/2011/250350

[10] H. Xiao, Introduction to Semiconductor Manufacturing Technology. Prentice Hall, 2001.

[11] H. O. Pierson, Handbook of Chemical Vapor Deposition, 2nd Edition: Principles, Technology and Applications. Elsevier Science, 1999.