Passive TCF compensation in high Q silicon micromechanical resonators

Samarao, Ashwin K.; Casinovi, G.; Ayazi, Farrokh

doi:10.1109/memsys.2010.5442553

Cited by 58 publications

(26 citation statements)

References 7 publications

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“…1 1 The originally submitted pre-conference abstract for this paper discussed a frequency jump observed for certain devices at a time t < −220 days. This was erroneously identified as a burn-in effect, and in reality the reason was a change in the drive amplitude of these resonators.…”

Section: Resultsmentioning

confidence: 99%

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Long term stability and quality factors of degenerately n-type doped silicon resonators

Jaakkola

Gorelick

Prunnila

et al. 2014

2014 IEEE International Frequency Control Symposium (FCS)

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Effect of degenerate doping on the long term stability and quality factors of silicon resonators was studied. The long term stability of electrostatically coupled tuning fork and width extensional mode resonators was found to be better than 1 ppm during a measurement spanning 220 days. Resonators were phosphorus doped to a carrier concentration of 4.1 × 10 19 cm −3 . Quality factors of~10-MHz Lamé mode resonators on wafers doped up to a concentration of 7.5 × 10 19 cm −3 were found to range from 900,000 to 1,500,000, which is comparable to that reported for similar resonators with moderate doping. The results indicate that the effect from heavy phosphorus doping on resonator stability or on silicon intrinsic losses is low at the studied doping levels.

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Section: Resultsmentioning

confidence: 99%

“…Degenerate doping of silicon has been found as a viable way of reducing the temperature dependency of the frequency of MEMS resonators, and, in particular, n-type doping up to 7.5 × 10 19 cm −3 has been shown to be applicable to temperature compensation of a variety of flexural and bulk resonance modes [1], [2], [3], [4].…”

Section: Introductionmentioning

confidence: 99%

Long term stability and quality factors of degenerately n-type doped silicon resonators

Jaakkola

Gorelick

Prunnila

et al. 2014

2014 IEEE International Frequency Control Symposium (FCS)

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“…Achieving a highly stable oscillator output using silicon resonators is challenging given their large native temperature coefficient of frequency (TCF), which is approximately −30 ppm/°C. Passive compensation techniques, such as engineering device geometry [1] and substrate doping profile [2], have shown to reduce silicon resonator TCF to a few ppm/°C. Traditional methods using a layer of positive-TCF silicon dioxide to counteract the negative silicon TCF [3] are effective but require additional process steps and are limited to thin silicon substrates.…”

Section: Introductionmentioning

confidence: 99%

Dual-Mode AlN-on-Silicon Micromechanical Resonators for Temperature Sensing

Tabrizian

Ayazi

2014

IEEE Trans. Electron Devices

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In this paper, we present dual-mode (DM) AlNon-silicon micromechanical resonators for self-temperature sensing. In-plane width-shear (WS) and width-extensional (WE) modes of [110]-oriented silicon resonators have been used as alternatives to first-and third-order modes to enhance DM temperature sensitivity by engineering device geometry, which reduces inherent beat frequency f b between the two modes. This configuration provides a 50× improvement in temperature coefficient of beat frequency (TC f b ) compared with single-mode temperature measurement and eliminates the need for additional frequency multipliers to generate f b from its constituents.[100]-oriented WS/WE resonators provide 4× larger TCF difference between modes ( TCF) than first and third widthextensional resonators, which further contributes to TC f b enhancement. WS/WE mode resonators also demonstrate the capability of operating as a temperature-stable reference f b . The proposed modes for DM operation have high Q and low motional resistance, and are 180°out-of-phase when operated in two-port configuration, thus enabling mode-selective low-power oscillator interfacing for resonant temperature sensing.

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“…First experiments showing reduced temperature drift were achieved with p-type doping [1], but n-type doping soon appeared as a viable alternative [2]. Our work with bulk mode resonators has shown that n-type doping is an effective and versatile way of tailoring the temperature behavior of silicon resonators; we have demonstrated resonators with their f vs. T turnover point near room temperature, overcompensated devices (+18 ppm/K) [3], and shown that n-type doping is applicable to virtually all resonance modes of practical importance [4].…”

Section: Introductionmentioning

confidence: 99%