میکروفن خازنی با اندازه کوچک و حساسیت بالا با به کار گیری دیافراگم دایروی با مرکز ثابت

محورهای موضوعی : ادوات نیمه هادی

نسترن نادمی ¹ , جواد کرمدل ²

1 - کارشناس ارشد - دانشکده مهندسی برق – واحد تهران جنوب، دانشگاه آزاد اسلامی، تهران، ایران
2 - دانشیار - دانشکده مهندسی برق – واحد تهران جنوب، دانشگاه آزاد اسلامی، تهران، ایران

تاریخ دریافت : 1394/02/15 تاریخ پذیرش : 1394/09/28 تاریخ انتشار : 1394/11/01

کلید واژه: میکروفن خازنی, ولتاژ کششی, مبدل های صوتی, الکترواستاتیکی, سیستمهای میکرو الکترومکانیکی (MEMS),

چکیده مقاله :

در این مقاله، یک میکروفن خازنیMEMS جدید تک تراشه بر روی ویفر سیلیکونی با کمینه کردن اندازه و کاهش استحکام مکانیکی با استفاده از دیافراگم دایروی با مرکز ثابت پیشنهاد شده است. در میکروفن پیشنهادی دیافراگم شامل تعدادی حفره می‌باشد که موجب عبور هوا در شکاف مابین صفحه پشتی و دیافراگم می‌شود و به این ترتیب میرائی مربوط به صدا را در میکروفن کاهش می‌دهد. ‌تازگی این روش، ایجاد میکروفن دایروی با مرکز ثابت می‌باشد که قطر دیافراگم کمتر از میکروفن خازنی مرسوم به دست می‌آید. ابتدا تحلیل مکانیکی روی دیافراگم میکروفن انجام می‌گیرد تا ولتاژ کششی به دست آید. ولتاژ کششی میکروفن دایروی پیشنهادی 14 ولت می‌باشد. با توجه به ولتاژ کششی بدست آمده٬ ولتاژ بایاس به میکروفن اعمال شده و پارامترهای مختلف مانند ظرفیت خازنی و حساسیت اندازه‌گیری شد. با توجه به نتایج شبیه‌سازی کامسول (COMSOL)، میکروفن پیشنهادی با دیافراگم به قطر 400 میکرومتر و ضخامت 5/1 میکرومتر، حساسیت‌ 23- دسی‌بل را نشان داد. در مقایسه با کارهای قبلی، میکروفن پیشنهادی با ولتاژ تغذیه کمتر عملکرد فرکانسی بهتر و حساسیت بیشتری را برای سنس نمودن صدا عرضه می‌کند

چکیده انگلیسی:

In this paper, a new single-chip MEMS capacitor microphone on a silicon wafer by minimizing the size and the reduction of mechanical strength using a circular diaphragm with a fixed center is proposed. In the proposed microphone, the diaphragm includes a number of holes to pass the air through the gap between the back plate and diaphragm, and thus reduces the damping of the sound from the microphone. Novelty of this method, creating a circular microphone with fixed center, which the diameter of diaphragm is less than the conventional condenser microphone. At first, the mechanical analysis was conducted on microphone diaphragm in order to achieve the pull-in voltage. The pull-in voltage of the proposed circular microphone is 14 volts. According to the obtained pull-in voltage, the bias voltage were applied to the microphone, and various parameters such as capacitance and sensitivity were measured. Based on the simulation results of COMSOL, the proposed microphone with diaphragm diameter of 400 μm and a thickness of 1.5 μm, the sensitivity of -23 dB is shown. In comparison with previous works, the proposed microphone with lower supply voltage is provided the better frequency performance, and higher sensitivity, in order to sense the sound.

منابع و مأخذ:

[1] R.P. Scheeper, A.G.H. Van der Donk, W. Olthuis, P. Bergveld, “Fabrication of silicon condenser microphone using single wafer technology”, Journal of Microelectromechanical Systems, Vol. 1, No. 3, pp. 147-154, Sep. 1992.

[2] B.A. Ganji, B.Y. Majlis, “Design and fabrication of a new MEMS capacitive microphone using a perforated aluminum diaphragm”, Sensorsand Actuators A, Vol. 149, pp. 29-37, 2008.

[3]B.A. Ganjia, B.Y. Majlis, “High sensitivity and small size MEMS capacitiveذmicrophone using a novel slotted diaphragm”, Microsystem Technologies, Vol. 15, No. 9, pp. 1401-1406, Sep. 2009.

[4] B.A. Ganji, B.Y. Majlis, "Slotted capacitive microphone with sputtered aluminum diaphragm and photoresist sacrificial layer", Proceeding of the IEEE/ICSE, pp.267,271, June 2010.

[5] Cheng-Ta Yang, “The sensitivity analysis of a MEMS microphone with different membrane dimeters”, Journal of Marine Science and Technology, Vol. 18, No. 6, pp. 790-796, 2010.

[6] P.C.P. Chao,et.al, “A new hybrid fabrication process for a high sensitivity MEMS microphone”, Microsystem Technologies, Vol. 19, No. 9-10, pp. 1425-1431, Sep. 2013.

[7]P.R. Scheeper, B. Nordstrand, J.O. Gullfv, B. Liu, T. Clausen, L.Midjord, T. Storgaard-Larsen, “A new measurement microphone based on MEMS technology”, Journalof Microelectromech Systems, Vol. 12, No.6, pp. 880–890, Dec. 2003.

[8] P. Rombach, M. Mullenborn, U. Klein, K. Rasmussen, "The first low voltage, low noise differential silicon microphone, technology development and measurement results", Proceeding of the IEEE/MEMSYS, pp.42,45, Interlaken, Switzerland, Jan. 2001.

[9] X. Li, R. Lin, H. Kek, J. Miao, Q. Zou, "Sensitivity-improved silicon condenser microphone with a novel single deeply corrugated diaphragm ”, Sensors and Actuators A: Physical, Vol. 92, No. 1–3, pp. 257-262, Aug. 2001.

[10] A. Torkkeli, O. Rusanen, J. Saarilahti, H. Sepp ä, H. Sipola, J. Hi-etanen, “Capacitive microphone with low-stress polysilicon membrane and high-stress polysiliconbackplate”, Sensors and Actuators A: Physical, Vol. 85, No. 1–3, pp. 116-123, Aug. 2000.

[11] T. Ma, T.Y. Man, Y.C. Chan, Y. Zohar, M. Wong, "Design and fabrication of an integrated programmable floating-gate microphone", Proceeding of the IEEE/MEMSYS, pp.288,291, Las Vegas, NV, USA, Jan. 2002.

[12] P. Singh,” Modeling and characterization of microelectromechanicalsystems condenser microphone”, PhD Thesis, Texas Tech University, 2011.

[13] B. AzizollahGanji, M. Taybi, “Accurate model of capacitance for MEMS sensors using corrugated diaphragm with residual stress”, IJE Trans. A: Basics Vol. 27, No. 1, Jan. 2014.

[14] Q. Zou, Z. Li, L. Liu, "Design and fabrication of silicon condenser microphone using corrugated diaphragm technique", Journal of Microelectromechanical Systems, Vol. 5, No. 2, pp. 197-204, Sep. 1996.

[15] A. Torkkeli, O. Rusanen, J. Saarilahti, H. Seppa, H. Sipola, J. Hietanen, "Capacitive microphone with low-stress polysilicon membrane and high-stress polysiliconbackplate", Sensors and Actuators, A: Physical, Vol. 85, No. 1-3, pp. 116-123, Aug. 2000.

[16] J. Chen, L. Liu, Z. Li, Z. Tan, Y. Xu, J. Ma, "Single-chip condenser miniature microphone with a high sensitive circular corrugated diaphragm",  Proceedings of the IEEE/MEMS, pp. 284- 287, Las Vegas, NV, 2002.

[17] X. Li, R. Lin, H. Kek, J. Miao, Q. Zou, "Sensitivity-improved silicon condenser microphone with a novel single deeply corrugated diaphragm", Sensors and Actuators, A: Physical, Vol. 92, No. 1-3, pp. 257-262, Aug. 2001.

[18] H.J. Kim, S.Q. Lee, K.H. Park, "A novel capacitive type miniature microphone with a flexure hinge diaphragm", Proceedings of SPIE- The International Society for Optical Engineering, Boston, MA. 2006.

[19] J.W. Weigold, T.J. Brosnihan, J. Bergeron, X. Zhang, "A MEMS condenser microphone for consumer appl­ica­t­i­ons", Proceedings of the IEEE/MEMS, pp. 86-89, Istanbul, 2006.

[20] N. Mohamad, P. Iovenitti, T. Vinay, "High sensitivity capacitive MEMS microphone with spring supported diaphragm", Proceedings of SPIE - The International Society for Optical Engineering, 2008.

[21] S.D. Senturia, “Microsystems design”, Kluwer Academic Publishers, pp. 12-56, 2000.

[22] P.R. Scheeper, A.G.H. Van der Donk, W. Olthuis, P. Bergveld, “Fabrication of silicon condenser microphone using single wafer technology”,  Journal of Microelectromechanical Systems, Vol. 1, No. 3, pp. 147-154, 1992.

[23] A. Torkkeli, O. Rusanen, J, Saarilahti, H., Seppa, H., Sipola, J., Hietanen, “Capacitive microph one with low-stress polysiliconmem-brane and high-stress polysiliconbackplate”, Sensors and Actuators A: Physical, Vol. 85, No. 1–3, pp. 116-123, Aug. 2000.

[24] L. Picolli, M. rassi, L. Rosson, P. Malcovati, A. Fornasari, "A 1.0 mW, 71 dB SNDR, −1.8 dBFS input swing, fourth-order ΣΔ interface circuit for MEMS microphones", Proceeding of the IEEE/ESSCIRC, pp. 324-327, Athens, Sep. 2009.

[25] D.T. Blackstock, “Fundamentals of physical acoustics”, California: John Wiley & Sons, Inc, Ch. 4, 14, 2000.

[26] P.R. Scheeper,A.G.H. Van der Donk, W. Olthuis, P. Bergveld, “A review of silicon microphones”,Sensors and Actuators A: Physical, Vol. 44, pp. 1–11, 1994.

[27] Z. ˇSkvor, “On the acoustical resistance due to viscous losses in the air gap of electrostatic transducers,” Acustica, Vol. 19, pp. 295–299, 1967.

[28] J. Bergqvist, F. Rudolf, “A Silicon condenser microphone using bond and etch-back technology”, Sens. Actuators A, Vol. 45, pp. 115–124, 1994.

[29] M. Iwaki, “High-quality sound pickup method at the viewpoint of the program production”, Presented at the Kansai-Section Joint Convention of Institutes of Electrical Engineering Japan, S11-5, 2005.

[30] J. Bergqvist, “Finite-element modelling and characterization of a silicon condenser microphone with a highly perforated backplate”, Sensors and Actuators, A: Physical, Vol. 39, No. 3, pp. 191-200, 1993.