Authors: A. Muller, G. Konstantinidis, A. Dinescu, A. Stefanescu, A. Cismaru, V. Buiculescu, I. Giangu, G. Stavrinidis, A. Stavrinidis
Affilation: IMT Bucharest, Romania
Pages: 423 - 426
Keywords: SAW, GaN, temperature sensor, microwave, resonator
The use of GaN based SAW type sensors has a major advantage for temperature measurements in GaN MMICs because of the possibility of monolithic integration of the temperature sensor and the possibility to place the sensing structure very close to the hot areas of the circuit. The temperature sensor we have developed consists in a single resonator GaN structure and reflection measurements (the S11 parameter) are used for resonance frequency vs. temperature determinations. The structure was manufactured using a deep submicronic e-beam nano-lithographic process on GaN/Si having as result a resonance frequency around 5 GHz. Fingers and interdigit spacing were 200 nm wide The very high resonance frequency has as effect an increase of the sensitivity, to a few hundred of kHz/oC. This simplifies the signal processing electronics. The single resonator structure was measured in the 23-130oC temperature range. The dependence of resonance frequency vs. temperature can be linear approximated; an increase of more than 20% was obtained for the sensitivity of the single resonator structure compared to the two face-to-face resonator structure.