J. Giner

Integration of RF-MEMS resonators on submicrometric commercial CMOS technologies

Integration of electrostatically driven and capacitively transduced MEMS resonators in commercial CMOS technologies is discussed. A figure of merit to study the performance of different structural layers and different technologies is defined. High frequency (HF) and very high frequency (VHF) resonance MEMS metal resonators are fabricated on a deep submicron 0.18 µm commercial CMOS technology and are characterized using electrical tests without amplification, demonstrating the applicability of the MEMS fabrication process for future technologies. Moreover, the fabricated devices show comparable performance in terms of Q × fres with previously presented MEMS resonators, whereas the small gap allows obtaining a low motional resistance with a single resonator approach.

A CMOS–MEMS RF-Tunable Bandpass Filter Based on Two High-

This letter presents the design, fabrication, and demonstration of a CMOS-MEMS filter based on two high-Q submicrometer-scale clamped-clamped beam resonators with resonance frequency around 22 MHz. The MEMS resonators are fabricated with a 0.35-mum CMOS process and monolithically integrated with an on-chip differential amplifier. The CMOS-MEMS resonator shows high-quality factors of 227 in air conditions and 4400 in a vacuum for a bias voltage of 5 V. In air conditions, the CMOS-MEMS parallel filter presents a programmable bandwidth from 100 to 200 kHz with a <1-dB ripple. In a vacuum, the filter presents a stop-band attenuation of 37 dB and a shape factor as low as 2.5 for a CMOS-compatible bias voltage of 5 V, demonstrating competitive performance compared with the state of the art of not fully integrated MEMS filters.

Q

A novel technique for global packaging of MEMS devices using standard CMOS technology is presented. A MEMS polysilicon resonator is fabricated and on-chip packaged using two metal layers already available from the CMOS technology. A simple buffered HF wet etching process is performed in house to release the MEMS resonator while metal deposition is used to vacuum seal the zero-level package. Both post-processing steps are carried out on CMOS chips. The design of the metal layers is carefully done in order to avoid the degradation of the MEMS. The electrical frequency response of the resonator is used for testing the performance of the final package. Electrical measurements and physical characterization demonstrate proper performance of the MEMS resonator and package.

22-MHz Polysilicon Clamped-Clamped Beam Resonators

In this paper, a novel fully integrated CMOS-MEMS filter implemented on a commercial CMOS technology is presented. The combination of mechanical and electrical coupling is used to enhance the response of the band pass filter. In particular, a 20 dB shape factor as low as 2 and a 35 dB stopband rejection are achieved. Moreover, the topology of the device allows obtaining a dual-bandpass filter behavior, presenting a tunable bandwidth and a deep notch between bands. Results show a dual-band filter with a 22 dB inner stopband rejection, center frequencies at 27.5 and 27.8 MHz, respectively, and a 0.6% relative bandwidth.

Zero-level packaging of MEMS in standard CMOS technology

In this paper a fully integrated CMOS-MEMS filter is presented. The filter is formed by two beams using a V-shaped coupler which allows the in-plane vibrations. The device presents a BW of 1.85MHz for a 29MHz center frequency. The electrical phase inversion mechanism is used in order to obtain the filter response. The device is fabricated using the capacitance module present in the commercial CMOS technology from Austria Micro-systems 0.35 µm.

A fully integrated programmable dual-band RF filter based on electrically and mechanically coupled CMOS-MEMS resonators

Clamped-clamped beam resonators are designed and fabricated in a 0.35µm CMOS commercial technology, using a simple one-step mask-less wet etching to release the MEMS structures. The resonator, with a 22MHz resonance frequency shows a Q value of 227 and 4400, when measured at atmospheric pressure and vacuum, respectively. This resonator is used as the main building block for filtering application. Using parallel filtering and differential on-chip CMOS amplification, the RF-CMOS-MEMS system forms a tunable band-pass filter with programmable bandwidth (from 100kHz to 200kHz), stop band rejections of 30 dB and shape factors at −20dB smaller than 3, providing comparable performance than other MEMS filters using specific technologies.

A CMOS-MEMS filter using a V-coupler and electrical phase inversion

In this work, the characterization of the first lateral in-plane flexural mode DETF (Double Ended Tuning Fork) MEMS resonator integrated monolithically in a CMOS 0.35µm technology is done. This characterization is done with the same resonator stand-alone and with an integrated CMOS amplifier to obtain the handling dynamic range of the applied voltage (dc bias and ac signal) for a linear behavior of the resonator.

High Q CMOS-MEMS resonators and its applications as RF tunable band-pass filters

Experimental results of a pulsed mode electrostatic excitation on a Double Ended Tunning Fork (DETF) MEMS resonator at 11 MHz fabricated on a commercial standard 0.35um CMOS technology are described. Using small pulse widths of 4 ns, a ten percent power safe and a reduction of the MEMS non-linearities are achieved.

Linear operation of a 11MHz CMOS-MEMS resonator

In this paper a 25 MHz free-free beam flexural resonator monolithically integrated in a 0.35 um CMOS technology is presented. A comparison between the frequency response and electrical characteristics between free-free beam and clamped-clamped beams shows higher qualities factor for free-free beams which will allow better oscillators for frequency references in terms of phase noise.

Characterization of CMOS-MEMS resonator by pulsed mode electrostatic actuation

A double-ended tuning fork (DETF) fabricated in a 0.35 um commercial CMOS technology is presented. Resonator performance for the application of this device in a RF front-end is measured using electrical test. DEFT offers a higher isolation between ports than clamped -clamped beams and the possibility to create a band-pass for frequency filtering or mixing using a single resonator. Discrepancies between expected and obtained results are studied using FEM mechanical simulations.