A fully-differential CMOS-MEMS resonator integrated with an on-chip amplifier

As one of the core components of MEMS (i.e., micro-electro-mechanical systems), thin-film piezoelectric-on-silicon (TPoS) resonators experienced a blooming development in the past decades due to unique features such as a remarkable capability of integration for attractive applications of system-on-chip integrated timing references. However, the parasitic capacitive feedthrough poses a great challenge to electrical detection of resonance in a microscale silicon-based mechanical resonator. Herein, a fully-differential configuration of a TPoS MEMS resonator based on a novel structural design of dual interdigital electrodes is proposed to eliminate the negative effect of feedthrough. The fundamental principle of feedthrough suppression was comprehensively investigated by using FEA (i.e., finite-element analysis) modeling and electrical measurements of fabricated devices. It was shown that with the help of fully-differential configuration, the key parameter of SBR (i.e., signal-to-background ratio) was significantly enhanced by greatly suppressing the in-phase signal. The S-parameter measurement results further verified the effectiveness of this novel feedthrough suppression strategy, and the insertion loss and SBR of proposed TPoS resonators were improved to 4.27 dB and 42.47 dB, respectively.

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CMOS MEMS resonator oscillator with an on-chip boost DC/DC converter

2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS) ◽

10.1109/transducers.2015.7181342 ◽

2015 ◽

Cited By ~ 3

Author(s):

S.H. Tseng ◽

Y.T. Hsieh ◽

C.C. Lin ◽

H.H. Tsai ◽

Y.Z. Juang

Keyword(s):

Mems Resonator ◽

Cmos Mems ◽

On Chip

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Fabrication of Monolithic Integrated Bimaterial Resonant Uncooled IR Sensor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.543.176 ◽

2013 ◽

Vol 543 ◽

pp. 176-179 ◽

Cited By ~ 1

Author(s):

D.Q. Zhao ◽

Xia Zhang ◽

P. Liu ◽

F. Yang ◽

C. Lin ◽

...

Keyword(s):

Silicon Nitride ◽

Hole Mobility ◽

Micro Electro Mechanical System ◽

Cmos Process ◽

Standard Cmos Process ◽

Ir Sensor ◽

Cantilever Structure ◽

Cmos Mems ◽

On Chip ◽

Micro Cantilever

In this work we studied the fabrication of a monolithic bimaterial micro-cantilever resonant IR sensor with on-chip drive circuits. The effects of high temperature process and stress induced performance degradation were investigated. The post-CMOS MEMS (micro electro mechanical system) fabrication process of this IR sensor is the focus of this paper, starting from theoretical analysis and simulation, and then moving to experimental verification. The capacitive cantilever structure was fabricated by surface micromachining method, and drive circuits were prepared by standard CMOS process. While the stress introduced by MEMS films, such as the tensile silicon nitride which works as a contact etch stopper layer for MOSFETs and releasing stop layer for the MEMS structure, increases the electron mobility of NMOS, PMOS hole mobility decreases. Moreover, the NMOS threshold voltage (Vth) shifts, and transconductance (Gm) degrades. An additional step of selective removing silicon nitride capping layer and polysilicon layer upon IC area were inserted into the standard CMOS process to lower the stress in MOSFET channel regions. Selective removing silicon nitride and polysilicon before annealing can void 77% Vth shift and 86% Gm loss.

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A Tunable-Gain Transimpedance Amplifier for CMOS-MEMS Resonators Characterization

Micromachines ◽

10.3390/mi12010082 ◽

2021 ◽

Vol 12 (1) ◽

pp. 82

Author(s):

Rafel Perelló-Roig ◽

Jaume Verd ◽

Sebastià Bota ◽

Jaume Segura

Keyword(s):

Cmos Technology ◽

Open Loop ◽

Transimpedance Amplifier ◽

Mems Devices ◽

Monolithically Integrated ◽

Mems Resonators ◽

Electromechanical Performance ◽

Cmos Mems ◽

Promising Solution ◽

On Chip

CMOS-MEMS resonators have become a promising solution thanks to their miniaturization and on-chip integration capabilities. However, using a CMOS technology to fabricate microelectromechanical system (MEMS) devices limits the electromechanical performance otherwise achieved by specific technologies, requiring a challenging readout circuitry. This paper presents a transimpedance amplifier (TIA) fabricated using a commercial 0.35-µm CMOS technology specifically oriented to drive and sense monolithically integrated CMOS-MEMS resonators up to 50 MHz with a tunable transimpedance gain ranging from 112 dB to 121 dB. The output voltage noise is as low as 225 nV/Hz1/2—input-referred current noise of 192 fA/Hz1/2—at 10 MHz, and the power consumption is kept below 1-mW. In addition, the TIA amplifier exhibits an open-loop gain independent of the parasitic input capacitance—mostly associated with the MEMS layout—representing an advantage in MEMS testing compared to other alternatives such as Pierce oscillator schemes. The work presented includes the characterization of three types of MEMS resonators that have been fabricated and experimentally characterized both in open-loop and self-sustained configurations using the integrated TIA amplifier. The experimental characterization includes an accurate extraction of the electromechanical parameters for the three fabricated structures that enables an accurate MEMS-CMOS circuitry co-design.

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