Enhancing out-of-plane stroke in piezoelectrically driven micro-lens actuator with residual stress control

Chen, Ssu-Han; Michael, Aron; Kwok, Chee Yee

doi:10.1016/j.sna.2019.111620

Cited by 11 publications

(2 citation statements)

References 21 publications

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“…PECVD SiO 2 is a popular choice, both for masking during DRIE and as an insulating material. Several recent reports have also utilised PECVD SiO 2 [24][25][26][27] for PZT based MEMS fabrication. Good quality PECVD is usually obtained at elevated temperatures >300 • C. This high-temperature deposition, in some cases, is more than the Curie temperature of PZT (350 • C).…”

Section: Process Modificationmentioning

confidence: 99%

Low cost, contamination-free, and damage-free fabrication of PZT MEMS on SOI substrate

Tiwari¹,

Kumar²,

Dangi³

et al. 2021

J. Micromech. Microeng.

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This paper reports a generalised process flow for the fabrication of Lead Zirconate Titanate based Piezoelectric Micro Electromechanical System devices. The optimised process can be used to realise several devices with different 1-D and 2-D geometries on a single wafer. All the state-of-the-art fabrication methods introduce some damage to the active piezoelectric material. This damage entails the need for an additional step of recovery anneal in the fabrication process. Our process was designed and optimised to avoid any such damage to the PZT layer. Remnant polarisation and effective transverse piezoelectric coefficient (e31,f) were used as metrics to quantify the damage to the PZT layer. It is shown that our process does not damage the PZT thin film during the fabrication, and hence no recovery anneal is required. We observe a ~3x improvement in remnant polarisation and ~2x improvement in e31,f of PZT thin film compared to the PZT thin film subjected to our previous fabrication process. Moreover, the process explained here uses only wet chemical methods for patterning of contaminating agents (PZT and platinum), making it a cost-effective process.

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Section: Process Modificationmentioning

confidence: 99%

Low cost, contamination-free, and damage-free fabrication of PZT MEMS on SOI substrate

Tiwari¹,

Kumar²,

Dangi³

et al. 2021

J. Micromech. Microeng.

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show abstract

“…Besides in imaging systems, such devices are used in laser scanning systems, laser micromachining, bar code readers, fiber switches and in projection systems. Technologies for the adjustment of focal length include displacement techniques, e.g., of lenses [ 1 , 2 ] or the use of metasurfaces [ 3 ] or the control of fluids (electrowetting) [ 4 ]. Another widely used method is the construction of deformable mirrors in the form of membranes (called in this paper FMM: focusing membrane mirrors) that are deformed into a parabolic shape to create a focal point for incident light thus forming reflective lenses where a defined, mostly parabolic membrane deformation can be achieved by electrostatic forces between the membrane as deformable electrode and a suitable, fixed counter electrode.…”

Section: Introductionmentioning

confidence: 99%

Evaluation and Optimization of a MOEMS Active Focusing Device

Mescheder

Lootze

Aljasem³

2021

Micromachines

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In this paper we present a detailed evaluation of a micro-opto-electromechanical system (MOEMS) for active focusing which is realized using an electrostatically deformed thin silicon membrane. The evaluation is done using finite element methods and experimental characterization of the device behavior. The devices are realized in silicon on insulator technology. The influence of internal stress especially resulting from the high compressive buried oxide (BOX) layer is evaluated. Additionally, the effect of stress gradients in the crystalline device layer and of high reflective coatings such as aluminum is discussed. The influence of variations of some important process steps on the device performance is quantified. Finally, practical properties such as focal length control, long-term stability, hysteresis and dynamical response are presented and evaluated. The evaluation proves that the proposed membrane focusing device is suitable for high performance imaging (wavefront errors between λ/5–λ/10) with a large aperture (5 mm).

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On large deformation and stability of microcantilevers under follower load

Dehrouyeh-Semnani

2021

International Journal of Engineering Science

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Enhancing out-of-plane stroke in piezoelectrically driven micro-lens actuator with residual stress control

Cited by 11 publications

References 21 publications

Low cost, contamination-free, and damage-free fabrication of PZT MEMS on SOI substrate

Low cost, contamination-free, and damage-free fabrication of PZT MEMS on SOI substrate

Evaluation and Optimization of a MOEMS Active Focusing Device

On large deformation and stability of microcantilevers under follower load

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