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

Area of Science:

• Materials Science
• Sensor Technology
• Semiconductor Physics

Background:

• Silicon-on-insulator (SOI) and silicon-on-sapphire (SOS) pressure sensors face limitations above 500 °C due to plastic deformation and current leakage.
• Silicon carbide (SiC) offers superior mechanical and electrical stability at high temperatures, making it ideal for advanced sensor applications.
• Processing challenges, particularly deep etching, have hindered the widespread use of SiC in high-temperature pressure sensors.

Purpose of the Study:

• To develop an effective fabrication method for piezoresistive silicon carbide (SiC) pressure sensors.
• To overcome the processing difficulties associated with SiC, especially deep etching.
• To demonstrate the high-temperature performance and accuracy of the fabricated SiC pressure sensor.

Main Methods:

• Fabrication involved a combination of inductive coupled plasma (ICP) dry etching, high-temperature rapid annealing, and femtosecond laser deep etching.
• The developed SiC pressure sensor underwent static and dynamic calibration tests.
• Performance was evaluated across a wide temperature range, from -50 °C to 600 °C.

Main Results:

• The fabricated SiC pressure sensor achieved an accuracy error of 0.33%FS.
• The sensor exhibited a rapid dynamic signal response time of 1.2 μs.
• The sensor successfully operated within the temperature range of -50 °C to 600 °C.

Conclusions:

• The proposed fabrication method effectively addresses SiC processing challenges, particularly deep etching.
• The developed piezoresistive SiC pressure sensor demonstrates high accuracy and fast response suitable for high-temperature environments.
• This work validates the feasibility of using SiC for robust high-temperature pressure sensing applications.