Highly sensitive 4H-SiC pressure sensor at cryogenic and elevated temperatures. (15th October 2018)

• Record Type: Journal Article
• Authors: Nguyen, Tuan-Khoa; Phan, Hoang-Phuong; Dinh, Toan; Dowling, Karen M.; Foisal, Abu Riduan Md; Senesky, Debbie G.; Nguyen, Nam-Trung; Dao, Dzung Viet
• Is Part Of: Materials & design. Volume 156(2018)
• Page Start: 441
• Page End: 445
• Publication Date: 2018-10-15
• Subjects: Piezoresistive -- Pressure sensor -- Silicon carbide; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2018.07.014
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: The slow etching rate of conventional micro-machining processes is hindering the use of bulk silicon carbide materials in pressure sensing. This paper presents a 4H-SiC piezoresistive pressure sensor utilising a laser scribing approach for fast prototyping a bulk SiC pressure sensor. The sensor is able to operate at a temperature range from cryogenic to elevated temperatures with an excellent linearity and repeatability with a pressure of up to 270 kPa. The good optical transparency of SiC material allows the direct alignment between the pre-fabricated piezoresistors and the scribing process to form a diaphragm from the back side. The sensitivities of the sensor were obtained as 10.83 mV/V/bar at 198 K and 6.72 mV/V/bar at 473 K, which are at least a two-fold increment in comparison with other SiC pressure sensors. The high sensitivity and good reliability at either cryogenic and elevated temperatures are attributed to the profound piezoresistive effect in p-type 4H-SiC and the robust p-n junction which prevents the current from leaking to the substrate. This indicates the potential of utilising the laser scribing approach to fabricate highly sensitive bulk SiC pressure sensors for harsh environment applications. Graphical Abstract: Highlights: A highly sensitive bulk silicon carbide pressure sensor was fabricated using a laser scribing method. The sensor's sensitivity was obtained to be 10.83 mV/V/bar at 198 K and 6.72 mV/V/bar at 473 K. The sensor shows a two-fold increment of sensitivity in comparison with other silicon carbide pressure sensors. The as-fabricated sensor exhibits excellent sensitivity, linearity and reproducibility from cryogenic to elevated temperatures.