Recent Developments on Silicon Carbide Thin Films for Piezoresistive Sensors Applications (original) (raw)
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Effects of the Substrate on Piezoresistive Properties of Silicon Carbide Thin Films
2000
Silicon carbide (SiC), in bulk or film form, has been shown as a promising material to replace the silicon as sensing element in devices for harsh environments. This has motivated several studies on growth and characterization of SiC thin films on different substrates such as silicon, silicon dioxide (SiO 2 ), aluminum nitride (AlN) and silicon nitride (Si 3 N 4 ), among others. However, less attention has been given to the investigation on how substrates affect the piezoresistive properties of SiC thin films. In this work, we have investigated the effect of substrates on the piezoresistive properties of SiC thin films produced by magnetron sputtering. Three types of substrates were utilized: (100) monocrystalline silicon, AlN on silicon and thermally oxidized silicon. Test structures were fabricated using photolithography, metallization lift-off and RIE (reactive ion etching) processes in order to perform piezoresistive characterization of the SiC samples produced.
Applications of SiC-Based Thin Films in Electronic and MEMS Devices
The goal of this chapter is to discuss the role of in situ incorporation of nitrogen, oxygen, aluminum, boron, phosphorus and argon on the properties of SiC films. Special attention is given to the low temperature SiC growth processes. An overview on the applications of SiC-based thin films in electronic and MEMS devices is presented and discussed. Our recent researches on heterojunction diodes and MEMS sensors are emphasized.
The Piezoresistive Effect of SiC for MEMS Sensors at High Temperatures: A Review
Journal of Microelectromechanical Systems, 2015
Silicon carbide (SiC) is one of the most promising materials for applications in harsh environments thanks to its excellent electrical, mechanical, and chemical properties. The piezoresistive effect of SiC has recently attracted a great deal of interest for sensing devices in hostile conditions. This paper reviews the piezoresistive effect of SiC for mechanical sensors used at elevated temperatures. We present experimental results of the gauge factors obtained for various poly-types of SiC films and SiC nanowires, the related theoretical analysis, and an overview on the development of SiC piezoresistive transducers. The review also discusses the current issues and the potential applications of the piezoresistive effect in SiC. [2015-0092] Index Terms-Silicon carbide, piezoresistive effect, piezoresistance, harsh environments, microelectromechanical systems (MEMS).
3C-SiC HeteroEpitaxial Films for Sensors Fabrication
Advances in Science and Technology, 2008
Silicon Carbide (SiC) is a very promising material for the fabrication of a new category of sensors and devices, to be used in very hostile environments (high temperature, corrosive ambient, presence of radiation, etc.). The fabrication of SiC MEMS-based sensors requires new processes able to realize microstructures on bulk material or on the SiC surface. The hetero-epitaxial growth of 3C-SiC on silicon substrates allows one to overcome the traditional limitations of SiC microfabrication. This approach puts together the standard silicon bulk microfabrication methodologies with the robust mechanical properties of 3C-SiC. Using this approach we were able to fabricate SiC cantilevers for a new class of pressure sensor. The geometries studied were selected in order to study the internal residual stress of the SiC film. X-Ray Diffraction polar figure and Bragg-Brentano scan analysis were used to check to crystal structure and the orientations of the film. SEM analysis was performed to analyze the morphology of the released MEMS structures.
Progresses in Synthesis and Application of SiC Films: From CVD to ALD and from MEMS to NEMS
Micromachines, 2020
A search of the recent literature reveals that there is a continuous growth of scientific publications on the development of chemical vapor deposition (CVD) processes for silicon carbide (SiC) films and their promising applications in micro-and nanoelectromechanical systems (MEMS/NEMS) devices. In recent years, considerable effort has been devoted to deposit high-quality SiC films on large areas enabling the low-cost fabrication methods of MEMS/NEMS sensors. The relatively high temperatures involved in CVD SiC growth are a drawback and studies have been made to develop low-temperature CVD processes. In this respect, atomic layer deposition (ALD), a modified CVD process promising for nanotechnology fabrication techniques, has attracted attention due to the deposition of thin films at low temperatures and additional benefits, such as excellent uniformity, conformability, good reproducibility, large area, and batch capability. This review article focuses on the recent advances in the strategies for the CVD of SiC films, with a special emphasis on low-temperature processes, as well as ALD. In addition, we summarize the applications of CVD SiC films in MEMS/NEMS devices and prospects for advancement of the CVD SiC technology.
Single crystal 3C-SiC films were grown on and Si substrate orientations in order to study the resulting mechanical properties of this material. In addition, poly-crystalline 3C-SiC was also grown on (100)Si so that a comparison with monocrystaline 3C-SiC, also grown on (100)Si, could be made. The mechanical properties of single crystal and polycrystalline 3C-SiC films grown on Si substrates were measured by means of nanoindentation using a Berkovich diamond tip. These results indicate that polycrystalline SiC thin films are attractive for MEMS applications when compared with the single crystal 3C-SiC, which is promising since growing single crystal 3C-SiC films is more challenging. MEMS cantilevers and membranes fabricated from a 2 µm thick single crystal 3C-SiC grown on (100)Si under similar conditions resulted in a small degree of bow with only 9 µm of deflection for a cantilever of 700 µm length with an estimated tensile film stress of 300 MPa. Single crystal 3C-SiC films on (111)Si substrates have the highest elastic and plastic properties, although due to high residual stress they tend to crack and delaminate.
Structural characterization of nanometer SiC films grown on Si
Applied Physics Letters, 1993
Continuous, ultrathin silicon carbide (Sic) films of less than 10 nm have been grown on Si by rapid thermal chemical vapor deposition carbonization with high propane flow rates at IlOO-1300 "C. X-ray and electron diffraction techniques indicated a monocrystalline structure for these nanometer-scale films. High-resolution transmission electron microscopy reveals that five Sic planes are aligned with four Si planes at the SiC/Si interface. The Fourier transform infrared spectrum of the Sic films exhibits the characteristic SGC absorption peak at around 800 cm-', with a FWHM of 45 cm-'.