A Contour Mode AIN Piezoelectric Resonator based on SOI Substrate

Fei, Sitao; Ren, Hao

doi:10.1109/nems50311.2020.9265593

Cited by 3 publications

(1 citation statement)

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“…The resonant frequency is 144.03 MHz, and the electromechanical coupling coefficient is 0.198%. Based on the results of previous studies [ 36 ], this paper mainly focuses on the temperature characteristics of the contour mode AlN resonator. A constant TCF of 9.1 ppm/°C is demonstrated in the measurement temperature range of 77 K to 400 K. The total structure is simply fabricated on a Silicon-on-Insulator (SOI) substrate.…”

Section: Introductionmentioning

confidence: 99%

Temperature Characteristics of a Contour Mode MEMS AlN Piezoelectric Ring Resonator on SOI Substrate

Fei

Ren

2021

Micromachines

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As a result of their IC compatibility, high acoustic velocity, and high thermal conductivity, aluminum nitride (AlN) resonators have been studied extensively over the past two decades, and widely implemented for radio frequency (RF) and sensing applications. However, the temperature coefficient of frequency (TCF) of AlN is −25 ppm/°C, which is high and limits its RF and sensing application. In contrast, the TCF of heavily doped silicon is significantly lower than the TCF of AlN. As a result, this study uses an AlN contour mode ring type resonator with heavily doped silicon as its bottom electrode in order to reduce the TCF of an AlN resonator. A simple microfabrication process based on Silicon-on-Insulator (SOI) is presented. A thickness ratio of 20:1 was chosen for the silicon bottom electrode to the AlN layer in order to make the TCF of the resonator mainly dependent upon heavily doped silicon. A cryogenic cooling test down to 77 K and heating test up to 400 K showed that the resonant frequency of the AlN resonator changed linearly with temperature change; the TCF was shown to be −9.1 ppm/°C. The temperature hysteresis characteristic of the resonator was also measured, and the AlN resonator showed excellent temperature stability. The quality factor versus temperature characteristic was also studied between 77 K and 400 K. It was found that lower temperature resulted in a higher quality factor, and the quality factor increased by 56.43%, from 1291.4 at 300 K to 2020.2 at 77 K.

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Section: Introductionmentioning

confidence: 99%