Femtosecond Laser Processing Assisted SiC High-Temperature Pressure Sensor Fabrication and Performance Test

Abstract

Due to material plastic deformation and current leakage at high temperatures, SOI (silicon-on-insulator) and SOS (silicon-on-sapphire) pressure sensors have difficulty working over 500 °C. Silicon carbide (SiC) is a promising sensor material to solve this problem because of its stable mechanical and electrical properties at high temperatures. However, SiC is difficult to process which hinders its application as a high-temperature pressure sensor. This study proposes a piezoresistive SiC pressure sensor fabrication method to overcome the difficulties in SiC processing, especially deep etching. The sensor was processed by a combination of ICP (inductive coupled plasma) dry etching, high-temperature rapid annealing and femtosecond laser deep etching. Static and dynamic calibration tests show that the accuracy error of the fabricated sensor can reach 0.33%FS, and the dynamic signal response time is 1.2 μs. High and low temperature test results show that the developed sensor is able to work at temperatures from −50 °C to 600 °C, which demonstrates the feasibility of the proposed sensor fabrication method.

Structural Engineering in Piezoresistive Micropressure Sensors: A Focused Review

“…In contrast, 6H-SiC and 4H-SiC can be epitaxially grown to produce commercial wafers for different all-SiC devices, and relevant pressure sensors have attracted significant attention. Wang et al reported a serial of all-4H-SiC pressure sensors with a measurement range of 5MPa, in which the sensing diaphragm was produced via laser micromachining of the 4H-SiC wafer [ 75 , 76 , 77 ]. The experimental results showed that a low hysteresis error of 0.17%FS and nonlinearity of 0.20%FS could be achieved at room temperature.…”