Robust SOI process without footing and its application to ultra high-performance microgyroscopes

Kim, Jongpal; Park, Sangjun; Kwak, Donghun; Ko, Hyoungho; Carr, W.N.; Buss, James R.; Cho, Dong‐il Dan

doi:10.1016/j.sna.2004.01.022

Cited by 19 publications

(8 citation statements)

References 6 publications

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“…We note that the explanation of an electrostatic deflection of incoming ions also has great resemblances to a phenomena known in reactive ion etching (RIE), called either notching or footing. [45][46][47] Further below, we demonstrate that the ionized vapor is indeed responsible for the fence-like features by mounting electrodes inside the evaporation chamber. These electrodes deflect the ionized metal atoms and consequently the fence-like structures disappear.…”

Section: Shadow Deposition Due To Ionized Metal Vapormentioning

confidence: 64%

How to solve problems in micro- and nanofabrication caused by the emission of electrons and charged metal atoms during e-beam evaporation

Volmer,

Seidler,

Bisswanger

et al. 2020

Preprint

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We discuss how the emission of electrons and ions during electron-beam-induced physical vapor deposition can cause problems in micro-and nanofabrication processes. After giving a short overview of different types of radiation emitted from an electron-beam (e-beam) evaporator and how the amount of radiation depends on different deposition parameters and conditions, we highlight two phenomena in more detail: First, we discuss an unintentional shadow evaporation beneath the undercut of a resist layer caused by the one part of the metal vapor which got ionized by electron-impact ionization. These ions first lead to an unintentional build-up of charges on the sample, which in turn results in an electrostatic deflection of subsequently incoming ionized metal atoms towards the undercut of the resist. Second, we show how low-energy secondary electrons during the metallization process can cause cross-linking, blisters, and bubbles in the respective resist layer used for defining micro-and nanostructures in an e-beam lithography process. After the metal deposition, the crosslinked resist may lead to significant problems in the lift-off process and causes leftover residues on the device. We provide a troubleshooting guide on how to minimize these effects, which e.g. includes the correct alignment of the e-beam, the avoidance of contaminations in the crucible and, most importantly, the installation of deflector electrodes within the evaporation chamber.

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Section: Shadow Deposition Due To Ionized Metal Vapormentioning

confidence: 64%

How to solve problems in micro- and nanofabrication caused by the emission of electrons and charged metal atoms during e-beam evaporation

Volmer,

Seidler,

Bisswanger

et al. 2020

Preprint

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“…Note that the plug-and-socket structure defines the position with a precision of few micrometers. After this assembly, SiO 2 wet etching follows to complete the development of the fiber stage [80]. The fiber stage structure can also be fabricated by the sacrificial bulk micromachining process [81].…”

Section: Fabrication Strategymentioning

confidence: 99%

Microelectromechanical-System-Based Design of a High-Finesse Fiber Cavity Integrated with an Ion Trap

Lee

Hong

et al. 2019

Phys. Rev. Applied

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We present a numerical study of a MEMS-based design of a fiber cavity integrated with an ion trap system. Each fiber mirror is supported by a microactuator that controls the mirror's position in three dimensions. The mechanical stability is investigated by a feasibility analysis showing that the actuator offers a stable support of the fiber. The actuators move the fibers' positions continuously with a stroke of more than 10 µm, with mechanical resonance frequencies on the order of kHz. A calculation of the trapping potential shows that a separation between ion and fiber consistent with strong ion-cavity coupling is feasible. Our miniaturized ion-photon interface constitutes a viable approach to integrated hardware for quantum information. * These authors contributed equally to this work. † tracy.northup@uibk.ac.at ‡ dicho@snu.ac.kr Au electrodes on fused silica. A MEMS surface ion trap has smaller trap depth than a three-dimensional Paul trap [19] but has the advantage of a reconfigurable planar trapping geometry, along with extensive optical access for laser beams, as required for a large-scale ion trap quantum computer. In 2016, a MEMS trap called the High Optical Access 2.0 trap was developed by Sandia National Laboratory [20], which is widely used by many ion trap researchers today. Topics of active research include the question of how to reduce stray charge accumulation, e.g., on the trap sidewalls [21] or via in situ cleaning [22,23], and how to build increasingly sophisticated structures, e.g., junction traps [24,25] for ion transport, and two-or three-dimensional electrode arrays [26,27].MEMS-based ion traps have advantages in scalability and ease of fabrication, and they can also be easily integrated with other type of MEMS devices. MEMS techniques can also reduce the footprint of the optical cavity system [28,29], particularly for the mirror actuators. The replacement of standard high-finesse mirrors by fiber mirrors has already reduced the physical cavity volume significantly [30,31]; however, when commercial nanopositioning stages are used, they place significant space demands on the in-vacuum assembly. Here, we propose and investigate a novel design for a MEMS-based fibercavity system integrated with a surface ion trap. The fiber system is studied by analyzing the mechanical stability, resonances, and stroke. Furthermore, we calculate the trapping potential seen by the ions in order to discuss the prospects for strong ion-cavity coupling. II. BASIC CONCEPTThe main structure consists of a surface ion trap integrated with a MEMS-based fiber cavity system ( Fig. 1(a)). The starting point is a microfabricated chip, arXiv:1907.07594v1 [quant-ph]

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“…A p-type, (111)-oriented, 4 inch singlecrystalline silicon wafer, which has resistivity of 1-10 Ω•cm, is used. The fabrication of the nanowire structure is performed by using the surface bulk micromachining (SBM) process [33][34][35]. First, as shown in figure 5(a), a thermal oxide film is grown by a wet oxidation process.…”

Section: Fabrication Processmentioning

confidence: 99%

Microelectrode array with integrated nanowire FET switches for high-resolution retinal prosthetic systems

Lee

Jung

Ahn

et al. 2014

J. Micromech. Microeng.

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In this paper, a novel microelectrode array integrated with nanowire field-effect transistor (FET) switches is developed for retinal prosthetic systems. Retinal prosthetic systems require many electrodes (generally more than several hundreds) and this paper presents a novel method of integrating silicon nanowire-FET switches with microelectrodes that can significantly reduce wiring complexity. Also, in order to fit the curvature of an eyeball, the silicon nanowire FETs are transferred to a flexible substrate. In order to demonstrate the concept of using FETs for switching collocated retinal microelectrodes, a microelectrode array with 32 × 32 pixels is fabricated, which has 1,024 microelectrodes. Using the FET switches in a two-dimensional array addressing configuration, 1,024 microelectrodes are addressed by only 64 lines (32 for scan and 32 for data), as compared to requiring 1,024 lines in the conventional one-to-one configuration. With the gate voltage of −5 V, the threshold voltage, current on/off ratio, and on-resistance of the fabricated silicon nanowire-FET switch are −0.4 V, 1 × 107, and 37–47 kΩ, respectively. The maximum allowable current injection limit of the silicon nanowire-FET switch integrated microelectrode is 44 μA with a pulse duration of 1 ms. These results show an excellent potential for high-resolution retinal prosthetic systems.

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Robust SOI process without footing and its application to ultra high-performance microgyroscopes

Cited by 19 publications

References 6 publications

How to solve problems in micro- and nanofabrication caused by the emission of electrons and charged metal atoms during e-beam evaporation

How to solve problems in micro- and nanofabrication caused by the emission of electrons and charged metal atoms during e-beam evaporation

Microelectromechanical-System-Based Design of a High-Finesse Fiber Cavity Integrated with an Ion Trap

Microelectrode array with integrated nanowire FET switches for high-resolution retinal prosthetic systems

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