Abstract
Silicon carbide (SiC) has promising potential for pressure sensing in a high temperature and harsh environment due to its outstanding material properties. In this work, a 4H-SiC piezoresistive pressure chip fabricated based on femtosecond laser technology was proposed. A 1030 nm, 200 fs Yb: KGW laser with laser average powers of 1.5, 3 and 5 W was used to drill blind micro holes for achieving circular sensor diaphragms. An accurate per lap feed of 16.2 μm was obtained under laser average power of 1.5 W. After serialized laser processing, the machining depth error of no more than 2% and the surface roughness as low as 153 nm of the blind hole were measured. The homoepitaxial piezoresistors with a doping concentration of 1019 cm−3 were connected by a closed-loop Wheatstone bridge after a rapid thermal annealing process, with a specific contact resistivity of 9.7 × 10−5 Ω cm2. Our research paved the way for the integration of femtosecond laser micromachining and SiC pressure sensor chips manufacturing.
Highlights
Silicon-based micro-electromechanical system (MEMS) sensors served great markets for pressure sensing in intermediate temperature applications range not exceeding
There are about 200 different polytypes of Silicon carbide (SiC), among which only 3C-SiC, 6H-SiC and 4H-SiC could be grown as single crystalline for applications in microelectronics and MEMS devices [8,9]
Due to the high-density defects caused by lattice mismatch, the nonuniform thickness of epitaxial films and the residual stress, the operating temperature of 3C-SiC pressure sensors does not exceed 400 ◦ C [10,11,12]
Summary
Silicon-based micro-electromechanical system (MEMS) sensors served great markets for pressure sensing in intermediate temperature applications range not exceeding200 ◦ C [1,2,3]. Silicon-based micro-electromechanical system (MEMS) sensors served great markets for pressure sensing in intermediate temperature applications range not exceeding. Silicon carbide (SiC) has long been regarded as an ideal material for high temperature applications thanks to its superior properties over silicon, such as wider bandgap, higher thermal conductivity and higher saturation velocity [7]. On the basis of the surface micromachining technology of epitaxial thin film on Si or SOI substrate, 3C-SiC was once the preferred material for high temperature pressure sensors. Due to the high-density defects caused by lattice mismatch, the nonuniform thickness of epitaxial films and the residual stress, the operating temperature of 3C-SiC pressure sensors does not exceed 400 ◦ C [10,11,12]. With the development of manufacturing techniques of large-scale semiconductor grades of 6H-SiC and 4H-SiC wafers, “all-SiC” pressure sensors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
