Investigation of Temperature Sensing Capabilities of GaN/SiC and GaN/Sapphire Surface Acoustic Wave Devices

Abstract

This paper proposes high sensitivity temperature sensors based on single port surface acoustic wave (SAW) devices with GHz resonance frequencies, developed on GaN/SiC and GaN/Sapphire, which permit wide range, accurate temperature determinations. In contrast with GaN/Si SAW based temperature sensors, SiC and Sapphire substrates enable the proper functionality of these devices up to 500 • C (773 K), as the high resistivity Si substrate becomes conductive at temperatures exceeding 250 • C (523 K) due to the relative low bandgap (and high intrinsic carrier concentrations). Low temperature measurements were carried out using a cryostat between -266 • C (7 K) and room temperature (RT) while the high temperature measurements are made on a modified RF probe station. A polynomial fit was used below RT and a linear approximation was evidenced between RT and 500 • C (773 K). The structures were simulated at different selected temperatures based on a method that couples Finite Element Method (FEM) and Coupling of Modes (COM). The measured temperature coefficient of frequency (TCF) is about 46 ppm/ • C for GaN/SiC SAWs and reaches values of 96 ppm/ • C for GaN/Sapphire SAW in the temperature range 25 -500 • C (298 K -773 K).INDEX TERMS Surface acoustic wave, temperature sensor, GaN, SiC, sapphire, high temperature measurements, low temperature measurements.

Experimental Analysis of Rayleigh and Sezawa Modes Resonance Frequencies in SAW Devices Manufactured on Sc0.3Al0.7N/Si†

“…are determined from COMSOL Multiphysics simulations. The first simulation is Short Circuit (SC) to extract series and parallel resonance frequencies, the second simulation is Frequency Domain to extract real admittance and the central resonant frequency; the last is Electrostatic simulation to calculate electrical capacitance of a single pair of fingers [21,22]. The periodicity of the structure enables the reduction of the 3D model to a 2D one, and moreover, the simulation of one pair of fingers.…”

Design and Research of Wireless Passive High-Temperature Sensor Based on SIW Resonance

“…Boldeiu et al designed a temperature sensor based on GaN/SiC and GaN/sapphire SAW, which permit wide range, accurate temperature determinations. The sensor can work stably at −266–500 °C [ 8 ].…”

Development of 3D Wafer Level Hermetic Packaging with Through Glass Vias (TGVs) and Transient Liquid Phase Bonding Technology for RF Filter

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