Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-17T19:38:24.770Z Has data issue: false hasContentIssue false
  • English
  • Français

Diamond-Like Carbon Films for Silicon Passivation in Microelectromechanical Devices

Published online by Cambridge University Press:  15 February 2011

M. R. Houston ,
R. T. Howe ,
K Komvopoulos  and
R. Maboudian
M. R. Houston
Affiliation:
Department of Chemical Engineering, Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720
R. T. Howe
Affiliation:
Department of Electrical Engineering and Computer Sciences, Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720
K Komvopoulos
Affiliation:
Department of Mechanical Engineering, Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720, California 94720
R. Maboudian
Affiliation:
Department of Chemical Engineering, Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720
Get access

Abstract

The surface properties of diamond-like carbon (DLC) films deposited by a vacuum arc technique on smooth silicon wafers are presented with specific emphasis given to stiction reduction in microelectromechanical systems (MEMS). The low deposition temperatures afforded by the vacuum arc technique should allow for easy integration of the DLC films into the current fabrication process of typical surface micromachines by means of a standard lift-off processing technique. Using X-ray photoelectron spectroscopy (XPS), contact angle analysis, and atomic force microscopy (AFM), the surface chemistry, microroughness, hydrophobicity, and adhesion forces of DLC-coated Si(100) surfaces were measured and correlated to the measured water contact angles. DLC films were found to be extremely smooth and possess a water contact angle of 87°, which roughly corresponds to a surface energy of 22 mJ/m2. It is shown that the pull-off forces measured by AFM correlate well with the predicted capillary forces. Pull-off forces are reduced on DLC surfaces by about a factor of five compared to 10 nN pull-off forces measured on the RCA-cleaned silicon surfaces. In the absence of meniscus forces, the overall adhesion force is expected to decrease by over an order of magnitude to the van der Waals attractive force present between two DLC-coated surfaces- To further improve the surface properties of DLC, films were exposed to a fluorine plasma which increased the contact angle to 99° and lowered the pull-off force by approximately 20% over that obtained with as-deposited DLC. The significance of these results is discussed with respect to stiction reduction in micromachines.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 383: Symposium I – Mechanical Behavior of Diamond and Other Forms of Carbon , 1995 , 391
Copyright
Copyright © Materials Research Society 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1 Lettington, A.H., in Thin Film Diamond, edited by Lettington, A. H. and Steeds, J.W., Chapman & Hall, London, (1994), p. 127.Google Scholar
2 Homola, A.M., Mate, C.M., and Street, G. B, MRS Bulletin 15, 45 (1990).Google Scholar
3 Howe, R.T., 13th Sensor Symposium, IEEE of Japan, June 8–9, 1995.Google Scholar
4 Muller, R. S., Sensors and Actuators A (Physical) A21, 1 (1990).Google Scholar
5 Alley, R.L., Cuan, G.J., Howe, R.T., and Komvopoulos, K., Proc. IEEE Solid-State Sensor and Actuator Workshop, Hilton Head Island, SC, June 21–25, 1992, p. 202.Google Scholar
6 Legtenberg, R., Elders, J., and Elwenspoek, M., Proc. 7th Int. Conf Solid-State Sensors and Actuators, Transducers 93, Yokohama, Japan, June 2–5, 1993, p. 198.Google Scholar
7 Bhushan, B., Tribology andMechanics of Magnetic Storage Devices, Springer-Verlag, New York, (1990).Google Scholar
8 Fedder, G.K., Ph. D.Thesis, Dept. of EECS, Univ. of Calif at Berkeley, Sept. 1994.Google Scholar
9 Deng, K., Collins, R.J., Mehregany, M., and Sukkenik, C.N., Proc. IEEE Micro Electro Mechanical Systems Workshop, Amsterdam, the Netherlands, Jan. 29 - Feb. 2, 1995, p. 368.Google Scholar
10 Mulhern, G.T., Soane, D.S., and Howe, R.T., Proc. 7th Int. Conf. Solid-State Sensors and Actuators, Transducers 93, Yokohama, Japan, June 2–5, 1993, p. 296.Google Scholar
11 Israelachvili, J.N., Intermolecular and Surface Forces, Academic Press, London, (1985).Google Scholar
12 Brown, I.G., Rev. Sci. Instrum. 65, 3061 (1994).Google Scholar
13 Anders, S., Anders, A., Brown, I.G., Wei, B., Komvopoulos, K., Ager, J.W. III, and Yu, K.M., Surf. Coat. Technol. 68/69, 388 (1994).Google Scholar
14 Veerasamy, V.S., Amaratunga, G.A.J., Davis, C.A., Timbs, A.E., Milne, W.I., and McKenzie, D. R., J. Phys.: Cond Matter 5, L169 (1993).Google Scholar
15 Anders, S., Anders, A., and Brown, I., J Appl. Phys. 74, 4239 (1993).Google Scholar
16 Alley, R.L., Komvopoulos, K., and Howe, R.T., J Appl. Phys. 76, 5731 (1994).Google Scholar
17 Komvopoulos, K., Wei, B., Anders, S., Anders, A., and Brown, I.G., J. Appl. Phys. 76, 1656 (1994).Google Scholar
18 Lifshitz, Y., Lempert, G.D., and Grossman, E., Phys. Rev. Lett. 72, 2753 (1994).Google Scholar
19 Houston, M.R. and Maboudian, R., submitted to.. Appl. Phys., (1995).Google Scholar
20 Neumann, A.W. and Good, R.J., in Surface and Colloid Science Vol. II: Experimental Methods, edited by Good, R.J. and Stromberg, R.R., Plenum Press, New York, (1979).Google Scholar
21 Feng, Z., Brewer, M.A., Komvopoulos, K., Brown, I.G., and Bogy, D.B., J. Mater. Res. 10, 165 (1995).Google Scholar
22 Good, R., in Contact Angle, Wettability, and Adhesion: Advances in Chemistry Series, edited by Fowkes, F.M., American Chemical Society, Washington, D.C., (1964), Vol.43.Google Scholar
23 Watanabe, N., Nakajima, T., and Touhara, H., Graphite Fluorides - Studies in Inorganic Chemistry, Elsevier, New York, (1988), Vol.8.Google Scholar
24 Scott, G., Polym. Eng. Sci. 24, 1007 (1984).Google Scholar
25 Merfeld, G.D. and Petrich, M.A., J. Vac. Sci. Technol. A 12, 365 (1994).Google Scholar
26 Wei, B. and Komvopoulos, K., J. Tribol 117, (1995), in press.Google Scholar
27 Torii, A., Sasaki, M., Hane, K., and Okuma, S., Proc. IEEE Micro Electro Mechanical Systems. An Invest. of Micro Structures, Sensors, Actuators, Machines, and Systems, Fort Lauderdale, FL, Feb. 7–10, 1993, p. 111.Google Scholar
28 Houston, M.R., Maboudian, R., and Howe, R. T., Proc. 8th int. conf Solid-Slate Sensors and Actuators, Transducers 95, Stockholm, Sweden, June 25–29, 1995.Google Scholar