A 4H-SiC CMOS Oscillator-Based Temperature Sensor Operating from 298 K up to 573 K.

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Devices

Background:

• High-temperature environments require robust sensing solutions.
• Existing sensors may face limitations in extreme temperature ranges.
• Silicon Carbide (SiC) CMOS technology offers potential for high-temperature operation.

Purpose of the Study:

• To develop and characterize a temperature sensor utilizing a 4H-SiC CMOS oscillator circuit.
• To evaluate the sensor's performance across a wide temperature range (298 K to 573 K).
• To analyze the impact of fabrication variations on sensor accuracy.

Main Methods:

• Design of a 4H-SiC CMOS oscillator circuit operating at 20 V bias and 90 kHz.
• Development of an analytical model for frequency-temperature dependency.
• Numerical simulations using the Verilog-A BSIM4SiC model.
• Monte Carlo analysis to assess fabrication process effects.

Main Results:

• Achieved near-linear frequency-temperature characteristics with R² > 0.9681.
• Maximum R² of 0.9992 observed at VDD = 12.5 V.
• Monte Carlo analysis showed a 17.4% deviation at 20% variance for threshold voltage and channel mobility.
• One-point calibration resulted in temperature errors of +8.8 K and -5.8 K at 15 V.

Conclusions:

• The proposed 4H-SiC CMOS oscillator circuit is a viable solution for high-temperature sensing.
• The sensor exhibits good linearity and acceptable accuracy after calibration.
• The technology demonstrates resilience to fabrication variations, crucial for reliable deployment.