A modular process for integrating thick polysilicon MEMS devices with sub-micron CMOS

Yasaitis, J.; Judy, Michael W.; Brosnihan, Tim; Garone, P.M.; Pokrovskiy, N.; Sniderman, Debbie; Limb, Scott J.; Howe, Roger T.; Boser, Bernhard E.; Palaniapan, M.; Jiang, Xinyi; Bhave, Sunil A.

doi:10.1117/12.478294

Cited by 30 publications

(15 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Four different parallel-plate actuators were designed to verify charge control as an effective actuation technique, as well as to verify the existence of the charge pull-in and tip-in instabilities. The charge control circuit and parallel-plate actuators were fabricated in the Analog Devices Mod MEMS process [16], which integrates a 6--thick structural-polysilicon layer with 0.8--CMOS electronics. A photograph of the die is shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Charge control of parallel-plate, electrostatic actuators and the tip-in instability

Seeger

Boser

2003

J. Microelectromech. Syst.

223

114

View full text Add to dashboard Cite

Controlling the charge, rather than the voltage, on a parallel-plate, electrostatic actuator theoretically permits stable operation for all deflections. Practically, we show that, using charge control, the maximum stable deflection is limited by 1) charge pull-in, in which the actuator snaps due to the presence of parasitic capacitance and 2) tip-in, in which the rotation mode becomes unstable. This work presents a circuit that controls the amount of charge on a parallel-plate, electrostatic actuator. This circuit reduces the sensitivity to parasitic capacitance, so that tip-in is the limiting instability. A small-signal model of the actuator is developed and used to determine the circuit bandwidth and gain requirements for stable deflections. Four different parallel-plate actuators have been designed and tested to verify the charge control technique as well as to verify charge pull-in, tip-in, and the bandwidth requirements. One design travels 83% of the gap before tip-in. Another design can only travel 20% of the gap before tip-in, regardless of whether voltage control or charge control is used.

show abstract

Section: Methodsmentioning

confidence: 99%

Charge control of parallel-plate, electrostatic actuators and the tip-in instability

Seeger

Boser

2003

J. Microelectromech. Syst.

223

114

View full text Add to dashboard Cite

show abstract

“…In order to modulate this field, the coupling is varied by a moving, grounded shutter. Taking a simplified example, if the field is normal to an electrode that has an effective area variation due to the oscillating shutter, the resulting current is (9) The current is converted to a voltage by the transresistance amplifier in Fig. 3; it is then amplified and detected by the lock-in amplifier.…”

Section: Theorymentioning

confidence: 99%

Electrostatic charge and field sensors based on micromechanical resonators

Riehl

Scott

Muller

et al. 2003

J. Microelectromech. Syst.

143

View full text Add to dashboard Cite

We have developed highly sensitive electrometers and electrostatic fieldmeters (EFMs) that make use of micromechanical variable capacitors. Modulation of the input capacitance, a technique used in macroscale instruments such as the vibrating-reed electrometer and the field-mill electrostatic voltmeter (ESV), moves the detection bandwidth away from the 1 -noise-limited regime, thus improving the signal-to-noise ratio (SNR). The variable capacitors are implemented by electrostatically driven resonators with differential actuation and sensing to reduce drive-signal feedthrough. The resonators in the electrometer utilize a balanced comb structure to implement harmonic sensing. Two fabrication methods were employed-a hybrid technology utilizing fluidically self-assembled JFETs and SOI microstructures, and an integrated process from Analog Devices combining 0.8-m CMOS and 6-m-thick polysilicon microstructures. All devices operate in ambient air at room temperature. Measured data from one electrometer with an input capacitance of 0.7 pF indicates a charge resolution of 4.5 aC rms (28 electrons) in a 0.3 Hz bandwidth. The resolution of this electrometer is unequaled by any known ambient-air-operated instrument over a wide range of source capacitances. The EFM has a resolution of 630 V/m, the best reported figure for a MEMS device.[985]Index Terms-Electrometer, electrostatic fieldmeter (EFM), electrostatic voltmeter, variable capacitor.

show abstract

“…(i) pre-CMOS: when the microsystem is manufactured before the CMOS circuitry [3,4], (ii) intra-CMOS: when the MEMS is manufactured between the regular fabrication steps of the CMOS circuit [5], (iii) post-CMOS, when the microsystem is manufactured after the CMOS circuit.…”

Section: Introductionmentioning

confidence: 99%

Experiments on the Release of CMOS-Micromachined Metal Layers

2010

View full text Add to dashboard Cite

We present experimental results on the release of MEMS devices manufactured using the standard CMOS interconnection metal layers as structural elements and the insulating silicon dioxide as sacrificial layers. Experiments compare the release results of four different etching agents in a CMOS technology (hydrofluoric acid, ammonium fluoride, a mixture of acetic acid and ammonium fluoride, and hydrogen fluoride), describe various phenomena found during the etching process, and show the release results of multilayer structures.

show abstract

A modular process for integrating thick polysilicon MEMS devices with sub-micron CMOS

Cited by 30 publications

References 1 publication

Charge control of parallel-plate, electrostatic actuators and the tip-in instability

Charge control of parallel-plate, electrostatic actuators and the tip-in instability

Electrostatic charge and field sensors based on micromechanical resonators

Experiments on the Release of CMOS-Micromachined Metal Layers

Contact Info

Product

Resources

About