ABSTRACT Nanosensitive mechanical microprobes with CMOS transistors, inverters, inverters cascades and ring oscillators, integrated on the thin silicon cantilevers are presented. Mechanical stress shifts linear, steep switching fragment of the inverters’ electrical characteristics. Microprobes were fabricated with use of the standard CMOS technology (3.5 μm design rules, one level polysilicon gate and one level of the metal interconnections) and relief MEMS technique. Control of the silicon cantilever thickness was satisfactory in the range above the few micrometers. Several computer simulations were done to analyze and optimize transistors location on the cantilever, in respect to the mechanical stress distribution. Results of the microprobes electromechanical tests confirm high deflection sensitivity 1.2 - 1.8 mV/nm and force sensitivity 2.0 - 2.4 mV/nN, both in nano ranges. Microprobes, with the ring oscillators revealed sensitivities 5 - 8 Hz/nm. These microprobes seem to be appropriate for applications in precise chemical and biochemical sensing.
Cite this paper
nullJ. Łysko, P. Dumania, P. Janus, M. Grodner, H. Kłos, K. Skwara and P. Grabiec, "Nanosensitive Silicon Microprobes for Mechanical Detection and Measurements," Materials Sciences and Applications, Vol. 2 No. 6, 2011, pp. 582-591. doi: 10.4236/msa.2011.26078.
 J. Bryzek, K. Petersen, J.R. Mallon Jr., L. Christel, F. Pourahmadi, “Silicon Sensors and Microstructures”, Ed. NovaSensor, Silicon Valey, 1990.
 R. Linnemann, T. Gotszalk, I.W. Rangelow, P. Dumania, E. Oesterschultze, “Atomic force microscopy and lateral force microscopy using piezoresistive cantilevers”, J. Vac. Sci. Technol., Vol. B 14 (2), 1996, pp. 856-860.
 J. Thaysen, A. Boisen, O. Hansen, S. Bouwstra, “Atomic force microscopy probe with piezoresistive read-out and highly symmetrical Wheatstone bridge arrangement”, Sensors and Actuators, Vol. A83, 2000, pp. 47-53.
 S.P. Timoshenko, “History of Strength of Materials”, New York: Dover Publ., 1983.
 G.L. Bir, G.E. Pikus, “Symmetry and Strain-induced Effects in Semiconductors”, Wiley - New York, 1972.
 Y. Kanda, “Piezoresistance Effect of Silicon”, Sensors and Actuators, Vol. A28, No. 2, 1991, pp. 83-91.
 C.S. Smith, “Piezoresistance Effect in Germanium and Silicon”, Phys. Rev., Vol. 94, No. 1, 1954, pp. 42-49.
 S.M. Sze, “Semiconductor Sensors”, Wiley - New York, 1994.
 C. Canall, C. Canali, G. Ferla, B. Morten, A. Taronif, “Piezoresistivity effects in MOS-FET useful for pressure transducers”, J. Phys. D: Appl. Phys., Vol. 12, 1979, pp. 1973-1983.
 Polish patent pending P.361525.
 P. Dumania, “Nanosensitive CMOS system for the silicon microbeam deformation measurements”, Proc. IX Conf. COE 2006, 2006, pp. 449-452 (in Polish).
 P. Dumania, et al, “CMOS ring oscillator as a detection unit for silicon nanosensitive microprobes”, Proc. X Conf. COE 2006, 2006, pp. 214-216 (in Polish).
 G. Shekhawat, S.-H. Tark, V.P. Dravid, “MOSFET- embedded microcantilevers for measuring deflection in biomolecular sensors”, Science, Vol. 311, 2006, pp. 1592- 1595.