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Enakshi Bhattacharya

Bio: Enakshi Bhattacharya is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Silicon & Surface micromachining. The author has an hindex of 14, co-authored 80 publications receiving 873 citations. Previous affiliations of Enakshi Bhattacharya include Indian Institutes of Technology & Tata Institute of Fundamental Research.


Papers
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Proceedings ArticleDOI
01 Dec 2007
TL;DR: In this article, the performance of composite membranes with MacroPS for pressure sensors was discussed and the sensitivity of the composite membrane is found to be higher compared to silicon and improves with the increase in the porosity due to the drastic reduction in Young's Modulus of PS with porosity.
Abstract: Silicon/porous silicon (Si/PS) composite membranes can be fabricated by converting a part of the silicon membrane thickness into porous silicon (PS) with electrochemical etching in HF based electrolyte. In this paper we discuss the performance of composite membranes with MacroPS for pressure sensors. The sensitivity of the composite membrane is found to be higher compared to silicon and improves with the increase in the porosity due to the drastic reduction in Young's Modulus of PS with porosity. The sensor response is found to be linear for pressures below 1 bar. PS formation produces stress in the membrane raising the offset voltage in the pressure sensors.

1 citations

Proceedings ArticleDOI
11 Feb 2010
TL;DR: In this paper, the design, process optimization and fabrication of a micro-mirror for Fourier Transform Spectrometry (FTS) was presented, where large, non-tilting displacements of mirrors are required to achieve high FTS resolution.
Abstract: A wide variety of MEMS micro-mirrors are being developed for various optical applications. One such application is Fourier Transform Spectrometry (FTS). The design, process optimization and fabrication of a micro-mirror for this application is presented. Large, non-tilting displacements of mirrors are required to achieve high FTS resolution. In order to obtain this without using Deep Reactive Ion Etching (DRIE), the micro-mirrors were fabricated on silicon using bulk micromachining techniques. This paper will present the process developed for fabrication of the mirror with the required specifications. In addition, results of the FTS experiments conducted with the micro-mirror will also be presented.

1 citations

Proceedings ArticleDOI
14 Oct 2003
TL;DR: In this article, the design and fabrication of polysilicon piezoresistive pressure sensor are presented, and the results obtained on the pressure sensors and the temperature coefficient of resistivity of poly-silicon resistors are presented.
Abstract: In this paper, the design and fabrication of polysilicon piezoresistive pressure sensor are presented. The design considerations such as the membrane thickness and the arrangement pattern of polysilicon piezo-resistors on the membrane are discussed with emphasis on the use of SOI approach. The results obtained on the pressure sensors and the temperature coefficient of resistivity of polysilicon resistors are presented. The results presented include the electrical trimming of polysilicon resistors for compensating zero offset voltage in the pressure sensors.

1 citations

01 Jan 2013
TL;DR: In this paper, a Digital Microfluidics (DMF) platform for handling fluidic sample delivery is presented, which is followed by the integration of the DMF chip with a microreactor that is an Electrolyte Insulator Semiconductor Capacitor (EISCAP) biosensor.
Abstract: We present the steps to fabricate a Digital Microfluidics (DMF) platform for handling fluidic sample delivery. This is followed by the integration of the DMF chip with a microreactor that is an Electrolyte Insulator Semiconductor Capacitor (EISCAP) biosensor. DMF is used for handling basic fluidic operations like droplet transportation, and splitting and dispensing smaller droplets from a reservoir. All the droplet operations on DI water droplets mentioned above are possible with AC actuation at ~35 V rms but this result in electrolysis on the transportation of an electrolyte droplet. DC actuation is used to solve the problem of electrolysis and to transport the electrolyte droplets. Interdigitated electrode geometry improves the device performance. The DMF substrate is used to deliver fluidic samples via a through hole in the DMF wafer to a bulk micromachined EISCAP biosensor bonded to the DMF wafer. The dimension of the through hole and the extent of its coverage with the control electrode are optimized for the successful delivery of the fluidic samples to the bonded biosensor below. The devices are tested by delivering droplets of electrolyte to the bonded reactor below. Capacitance-Voltage (C-V) measurement done on the integrated device confirms the successful delivery of the electrolyte to the microreactor. This integration technique can manipulate fluid handling work on the DMF substrate without compromising the functionality of the fluidic reactor.

1 citations

Proceedings ArticleDOI
07 Feb 2008
TL;DR: In this article, the fabrication and testing of Si/Porous Silicon (Si/PS) composite membranes where a part of the silicon membrane depth is converted into porous silicon was discussed.
Abstract: Since porous silicon (PS) has a lower Young’s Modulus as compared to silicon, Silicon/Porous Silicon (Si/PS) composite membranes are expected to show higher sensitivity as compared to membranes of silicon alone. In this paper we discuss the fabrication and testing of Si/PS composite membranes where a part of the silicon membrane depth is converted into PS. Composite membranes with Si/ microPS an d Si/ macroPS were fabricated with varying porosity and same thickness. The composite membranes with micro PS show higher sensitivity than composite membranes with macro PS. Formation of microporous and macroporous silicon produces stress on the membrane varying with the porosity. The variation in compressive stress on the membrane with porosity for both micro and macro PS has been studied by measuring the deformation of the composite membrane with a surface profiler and the stress is found to be larger for microPS. The compressive stress results in an increase in the offset voltage by more than an order of magnitude for composite membranes with porosity above 50% as compared to one with a single crystalline silicon one. Though the composite membranes exhibit saturation and hysteresis at higher pressures, the response is linear and repeatable at pressures below 1 bar making this a viable option for sensing low pressures. Keywords: MEMS, pressure sensor, porous silicon, porosity, stress, membrane, Young’s Modulus, sensitivity.

1 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: This work reviews the status of the various nanostructure-based biosensors and use of the self-assembly techniques and nano-electromechanical systems (NEMS) in bios Sensors is discussed.

506 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the pull-in phenomenon in electrostatically actuated MEMS and NEMS devices is presented, along with physical principles that have enabled fundamental insights into the pullin instability as well as pullin induced failures.
Abstract: Pull-in instability as an inherently nonlinear and crucial effect continues to become increasingly important for the design of electrostatic MEMS and NEMS devices and ever more interesting scientifically. This review reports not only the overview of the pull-in phenomenon in electrostatically actuated MEMS and NEMS devices, but also the physical principles that have enabled fundamental insights into the pull-in instability as well as pull-in induced failures. Pull-in governing equations and conditions to characterize and predict the static, dynamic and resonant pull-in behaviors are summarized. Specifically, we have described and discussed on various state-of-the-art approaches for extending the travel range, controlling the pull-in instability and further enhancing the performance of MEMS and NEMS devices with electrostatic actuation and sensing. A number of recent activities and achievements methods for control of torsional electrostatic micromirrors are introduced. The on-going development in pull-in applications that are being used to develop a fundamental understanding of pull-in instability from negative to positive influences is included and highlighted. Future research trends and challenges are further outlined.

442 citations

Journal ArticleDOI
TL;DR: This beautifully illustrated and well-written book, with an impressive array of authors, is aimed at both undergraduate and postgraduate level and emphasises the biochemistry of mammalian cells.
Abstract: Textbook of biochemistry with clinical correlations , 4th edn TM Devlin, ed pp xvii + 1186, illustrated Wiley-Liss, New York, 1997 £2995, hardback This beautifully illustrated and well-written book, with an impressive array of authors, is aimed at both undergraduate and postgraduate level As the editor states in the preface, it is not intended to be a compendium of biochemistry but rather emphasises the biochemistry of mammalian cells The first 22 chapters cover …

420 citations