An Approach on the Use of Co-sputtered W-DLC Thin Films as Piezoresistive Sensing Materials

Page: [3 - 9] Pages: 7

  • * (Excluding Mailing and Handling)

Abstract

Background: Miniaturized piezoresistive sensors, particularly strain gauges, pressure sensors, and accelerometers, have been used for measurements and control applications in various fields, such as automotive, aerospace, industrial, biomedical, sports, and many more. A variety of different materials have been investigated for the development of these sensors. Among them, diamond- like carbon (DLC) thin films have emerged as one of the most promising piezoresistive sensing materials due to their excellent mechanical properties, such as hardness and high Young’s modulus. At the same time, metal doping has been studied to enhance their electrical properties.

Objective: This article explores the use of co-sputtered tungsten-doped diamond-like carbon (WDLC) thin films as microfabricated strain gauges or piezoresistors.

Methods: Different serpentine thin-film resistors were microfabricated on co-sputtered W-DLC thin films using photolithography, metallization, lift-off and RIE (reactive ion etching) processes. In order to evaluate their piezoresistive sensing performance, Gauge Factor (GF) measurements were carried out at room temperature using the cantilever beam method.

Results: GF values obtained in this study for co-sputtered W-DLC thin films are comparable to those reported for W-DLC films produced and characterized by other techniques, which indicates the feasibility of our approach to using them as sensing materials in piezoresistive sensors.

Conclusions: W-DLC thin films produced by the co-magnetron sputtering technique can be considered as sensing materials for miniaturized piezoresistive sensors due to the following key advantages: (i) easy and well-controlled synthesis method, (ii) good piezoresistive properties exhibiting a GF higher than metals, and (iii) thin-film resistors formed by a simple microfabrication process.

Keywords: Diamond-like carbon, thin films, co-sputtering, metal doping, thin-film resistors, microsystem technology, piezoresistive sensors.

Graphical Abstract

[1]
Shi WL, Wei XT, Zhang W, Wang ZG, Dong CH, Li S. Developments and applications of diamond-like carbon. Appl Mech Mater 2017; 864: 14-24.
[http://dx.doi.org/10.4028/www.scientific.net/AMM.864.14]
[2]
Fraga MA, Furlan H, Pessoa RS, Massi M. Wide bandgap semiconductor thin films for piezoelectric and piezoresistive MEMS sensors applied at high temperatures: an overview. Microsyst Technol 2013; 2013(20): 9-21.
[3]
Li A, Li X, Wang Y, et al. Investigation of mechanical and tribological properties of super-thick DLC films with different modulation ratios prepared by PECVD. Mater Res Express 2019; 6: 086433.
[http://dx.doi.org/10.1088/2053-1591/ab1f5d]
[4]
Takeno T, Miki H, Takagi T. Strain sensitivity in Tungsten-containing diamond-like carbon films for strain sensor applications. Int J Appl Electromagn Mech 2008; 28: 211-7.
[http://dx.doi.org/10.3233/JAE-2008-978]
[5]
Petersen M, Heckmann U, Bandorf R, et al. Me-DLC films as material for highly sensitive temperature compensated strain gauges. Diamond Related Materials 2011; 20: 814-8.
[http://dx.doi.org/10.1016/j.diamond.2011.03.036]
[6]
Meškinis Š, Vasiliauskas A, Šlapikas K, et al. Bias effects on structure and piezoresistive properties of DLC:Ag thin films. Surf Coat Tech 2014; 255: 84-9.
[http://dx.doi.org/10.1016/j.surfcoat.2014.01.026]
[7]
Fraga MA, Furlan H, Pessoa RS, Rasia LA, Mateus CFR. Studies on SiC, DLC and TiO2 thin films as piezoresistive sensor materials for high temperature application. Microsyst Technol 2012; 18: 1027-33.
[http://dx.doi.org/10.1007/s00542-012-1435-y]
[8]
Takeno T, Miki H, Sugawara T, Hoshi Y, Takagi TA. DLC/W-DLC multilayered structure for strain sensing applications. Diamond Related Materials 2008; 17: 713-6.
[http://dx.doi.org/10.1016/j.diamond.2007.10.005]
[9]
Ohno T, Takeno T, Miki H, Takagi T. Microstructural design for fabrication of strain sensor utilizing tungsten-doped amorphous carbon coatings. Diamond Related Materials 2011; 20: 651-4.
[http://dx.doi.org/10.1016/j.diamond.2011.03.003]
[10]
Fevola G. Electrical characterization and modeling of SiC IC test structures. Sweden: Master of Science Thesis 2012.
[11]
Fraga MA, Furlan H, Rasia LA, Koberstein LL. Effects of the substrate on piezoresistive properties of silicon carbide thin films. ECS Trans 2012; 44: 1375-80.
[http://dx.doi.org/10.1149/1.3694474]
[12]
Leal G, Fraga MA, Cardoso GWA, da Silva Sobrinho AS, Massi M. Effect of metal target power on the properties of co-sputtered Sn-DLC and W-DLC thin films. 30th Symposium on Microelectronics Technology and Devices (SBMicro). 2015 31 Aug-4 Sept; Salvador, Brazil: IEEE
[http://dx.doi.org/10.1109/SBMicro.2015.7298111]