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Quantitative Analysis of Piezoresistive Characteristic Based on a P-type 4H-SiC Epitaxial Layer

1
Science and Technology on Electronic Test & Measurement Laboratory, North University of China, Taiyuan 030051, China
2
Department of Automation, Taiyuan Institute of Technology, Taiyuan 030051, China
*
Author to whom correspondence should be addressed.
Micromachines 2019, 10(10), 629; https://doi.org/10.3390/mi10100629
Received: 4 September 2019 / Revised: 18 September 2019 / Accepted: 18 September 2019 / Published: 20 September 2019
In this work, the piezoresistive properties of heavily doped p-type 4H-SiC at room temperature were investigated innovatively. It was verified by a field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and laser Raman spectroscopy (LRS) that the crystal quality of the epitaxial layer was good. The doping concentration and thickness of the epitaxial layer were measured by secondary ion mass spectrometry (SIMS) to be ~1.12 × 1019 cm−3 and ~1.1 µm, respectively. The 4H-SiC cantilever beam along [ 1 1 00 ] crystal orientation was fabricated, and the fixed end of the cantilever beam was integrated with longitudinal and transverse p-type 4H-SiC piezoresistors. A good ohmic contact was formed between Ni/Ti/Al/Au and a p-type 4H-SiC piezoresistor under nitrogen environment annealing at 1050 °C for 5 min. The free end of the cantilever beam was forced to cause strain on the p-type 4H-SiC piezoresistor, and then the resistances were measured by a high precision multimeter. The experimental results illustrated that longitudinal and transverse gauge factors (GFs) of the p-type 4H-SiC piezoresistors were 26.7 and −21.5, respectively, within the strain range of 0–336µε. In order to further verify the electro-mechanical coupling effect of p-type 4H-SiC, the piezoresistors on the beam were connected to the Wheatstone full-bridge circuit and the output changes were observed under cyclic loading of 0–0.5 N. The measuring results revealed that the transducer based on the 4H-SiC piezoresistive effect exhibited good linearity and hysteresis, which confirmed that p-type 4H-SiC has the potential for pressure or acceleration sensing applications. View Full-Text
Keywords: p-type 4H-SiC; piezoresistive effect; ohmic contact; cantilever beam p-type 4H-SiC; piezoresistive effect; ohmic contact; cantilever beam
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MDPI and ACS Style

Li, Y.; Liang, T.; Lei, C.; Hong, Y.; Li, W.; Li, Z.; Ghaffar, A.; Li, Q.; Xiong, J. Quantitative Analysis of Piezoresistive Characteristic Based on a P-type 4H-SiC Epitaxial Layer. Micromachines 2019, 10, 629.

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