1. Field of the Invention
Embodiments of the invention are generally directed to transducer type devices (see DEFINITIONS section) having a laminate structure including a layer with piezo properties (see DEFINITIONS section) and methods for making a transducer. More particularly, embodiments of the invention are directed to methods and/or devices relating to MEMS-scale or NEMS-scale transducers having a laminate structure including a layer with piezoresistive properties.
2. Background
Applications such as radio frequency (RF) signal processing and reference frequency oscillators, benefit from high quality factor, high frequency devices that have very small footprints, consume minimal power, and can be monolithically integrated with conventional microprocessor integrated circuit (IC) fabrication processes. Micro- or nano-mechanical resonators offer the possibility of achieving these goals.
An ongoing challenge surrounding micro- or nano-mechanical resonator structures and their utility in applications is measuring the motion of the resonators in a way that is readily incorporated into a real-world device. Methods currently used in the laboratory include optical and magnetomotive. Neither of these techniques is straightforward to implement in a device using standard fabrication techniques and requiring low cost and low power consumption. Electrical transduction methods exist but are less effective as device size is reduced to the micron and nanometer scale.
Some conventional transducer type devices use a layer with piezo resistive properties to actuate and or detect motion at the nano or microscale. As shown in FIG. 1, an example of such a conventional device 100 includes: first electrical contact (or simply first contact) 102; piezoresistive layer(s) 104; and second contact 106. In device 100, electricity is conducted through piezoresistive layer 104, along current path P1 along the major surface of the piezo layer, between contacts 102, 106. The characteristics of the electrical signal passing through P1 will change with the amount of stress or strain in piezoresistive layer 104, which means that the electrical characteristics of this signal will change as layer 104 moves. This relationship between the electrical signals and motion in layer 104 is what makes device 100 useful as a small scale (see DEFINITIONS section) transducer and/or actuator. It is noted that because electrical contacts 102, 106 are both on the same major surface of layer 104, the direction of signal P1 is in-plane (see DEFINITIONS section).
FIGS. 2 and 3 show device 200 including first contact 202, piezoresistive layer 204 and second contact 206. In device 200, the current path P2 is once again in-plane because both contacts 202 and 206 are on the same major surface of layer 204.
Other publications which may be of interest include: (i) US published patent application 2008/0068000 (“Bargatin”); (ii) U.S. Pat. No. 7,5q7,711 (“Naniwanda”); (iii) European patent Application EP 1 538 747 A1 (“Kihara”); (iv) US published patent application 2006/0098059 (“Ohguro”); (v) D. W. Carr, L. Sekaric, H. G. Craighead, J. Vac. Sci. Technol. B16, 3821 (1998); (vi) I. Bargatin, E. B. Myers, J. Arlett, B. Gudlewski, M. L. Roukes, Appl. Phys. Lett. 86, 133109 (2005); (vii) “RF MEMS Oscillator with Integrated Resistive Transduction” by R. B. Reichenbach, M. Zalalutdinov, J. M. Parpia, H. G. Craighead, IEEE Elec. Dev. Lett. 27, 805 (October 2006); (viii) P. A. Truitt, J. B. Hertzberg, C. C. Huang, K. L. Ekinci, K. C. Schwab, Nano Lett. 7, 120 (2007); (ix) R. J. Wilfinger, P. H. Bardell, D. S. Chhabra, IBM Journal, pp. 113-118 (1968); (x) N. Barniol, M. Villarroya, J. Verd, J. Teva, G. Abadal, E. Forsen, F. P. Murano, A. Uranga, E. Figueras, J. Montserrat, J. Esteve, A. Boisen, Sens. and Act. A 132, 154 (2006); (xi) S. Evoy, D. W. Can, L. Sekaric, A. Olkhovets, J. M. Parpia, H. G. Craighead, J. Appl. Phys. 86, 6072 (1999); (xii) L. Sekaric, M. Zalalutdinov, S. W. Turner, A. T. Zehnder, J. M. Parpia, H. G. Craighead, Appl. Phys. Lett. 80, 3617 (2002); (xiii) Y. Xie, S.-S. Li, Y.-W. Lin, Z. Ren, C. T.-C. Nguyen, IEEE Trans. on Ultra., Ferro., and Freq. Cont. 55, 890 (2008); (xiv) “Ultra-Sensitive NEMS-based cantivelevers for sensing, scanned probe and very high-frequency applications” by M. Li, H. X. Tang, M. L. Roukes, Nat. Nanotech. 2, 114 (28 Jan. 2007); (xv) V. Mosser, J. Suski, J. Goss, E. Obermeier, Sens. and Act. A 28, 113 (1991); (xvi) R. L. Parker, A. Krinsky, J. Appl. Phys. 34, 2700 (1963); (xvii) J. A. Harley, T. W. Kenny, Appl. Phys. Lett. 72, 289 (1999); (xviii) M. T. Kim, Thin Solid Films 283, 12-16 (1996); (xix) H. W. Ch. Postma, I. Kozinsky, A. Husain, M. L. Roukes, Appl. Phys. Lett. 86, 223105 (2005); (xx) A. H. Neyfeh, D. T. Mook, Nonlinear Oscillations, pp. 161-175 (John Wiley & Sons, New York, 1979); (xxi) W. Weaver Jr., S. P. Timoshenko, D. H. Young, Vibration Problems in Engineering, 5th ed., pp. 166-175 (John Wiley & Sons, New York, 1990); (xxii) R. He, X. L. Feng, M. L Roukes, P. Yang, Nano Lett. 8, 1756 (2008); and (xxiii) J. L. Artlett, J. R. Maloney, B. Gudlewski, M. Muluneh, M. L Roukes, Nano Lett. 6, 1000 (2006).
Description of the Related Art Section Disclaimer
To the extent that specific publications are discussed above in this Description of the Related Art Section, these discussions should not be taken as an admission that the discussed publications (for example, published patents) are prior art for patent law purposes. For example, some or all of the discussed publications may not be sufficiently early in time, may not reflect subject matter developed early enough in time and/or may not be sufficiently enabling so as to amount to prior art for patent law purposes. To the extent that specific publications are discussed above in this Description of the Related Art Section, they are all hereby incorporated by reference into this document in their respective entirety(ies).