The article aims to analyze the use of different compensation structures in MEMS micromachining technology to determine the minimum release time as fast as possible where undercutting is desirable. A high undercutting rate is advantageous for the formation of suspended structures. Thus, the implication of the present research includes analysis of corner undercutting behavior, their etching time, and etching characteristics using KOH and TMAH etchants. In this paper, the effective time and etchant concentration are studied using 33% KOH at 80, °C and 25% TMAH at 85, °C. It is found that wide bar with slit structure is the best compensation structure with minimum space competence. © Springer Nature Singapore Pte Ltd. 2018.

Ravi Sankar A

Electronics

School of Electronics Engineering

Chennai Campus

Grace Jency J

Sekar M

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Etch Time Optimization in Bulk Silicon MEMS Devices Using a Novel Compensation Structure

Lecture Notes in Electrical Engineering Microelectronics, Electromagnetics and Telecommunications

This paper presents fabrication and testing of a high performance quad beam silicon piezoresistive Z-axis accelerometer with a very-low cross-axis sensitivity. Cross-axis sensitivity in piezoresistive accelerometers, mainly caused by the asymmetric structural design is an important issue primarily for high performance applications. In the present study, symmetry of the structure is achieved by shifting the center of mass of the proof mass toward the beam plane by selectively electroplating a 20 μm thick gold layer atop the proof mass and simultaneously reducing the silicon thickness from backside of the proof mass surface. Silicon shadow mask technique was used to deposit a Cr/Au seed layer on the selected regions of the proof mass followed by an electroplating process to achieve the 20 μm thick gold layer. Theoretical analysis shows that for an in-plane acceleration, the rotation of the thickness reduced proof mass with the electroplated gold layer is reduced by 69% compared to the accelerometer device with normal all-silicon proof mass keeping the resonant frequency of both the structures nearly equal. The accelerometer device was realized by a bulk micromachining technique using a 5% dual doped tetra methyl ammonium hydroxide (TMAH) solution. A new figure of merit called the performance factor (PF) defined as the ratio of the product of the prime-axis sensitivity and the square of the resonant frequency to the maximum cross-axis sensitivity is used as a quantitative index to evaluate the fabricated sensors with already reported devices. Test results of a fabricated device with 30 μm flexure thickness show a very-low cross-axis sensitivity of 0.316 μV/Vg for an in-plane acceleration and a PF of around 2900 MHz2. © 2012 Elsevier B.V.

Sensors and Actuators A: Physical

A very-low cross-axis sensitivity piezoresistive accelerometer with an electroplated gold layer atop a thickness reduced proof mass

This Letter presents simulation, fabrication and testing of a high-performance quad-beam silicon piezoresistive accelerometer with very low cross-axis sensitivity. Cross-axis sensitivity in piezoresistive accelerometers is an important issue particularly for high-performance applications. In the present Letter, low cross-axis sensitivity is achieved by improving the device stability by placing four flexures in line with the proof mass edges. The accelerometer device is realised in a single-step double-sided bulk micromachining technique using a 5 dual-doped tetra methyl ammonium hydroxide solution as an anisotropic etchant. Test results of four fabricated devices show an average prime-axis sensitivity of 559.5μV/g/5V, a maximum cross-axis sensitivity of 0.62 full scale (FS acceleration=13g) of the prime-axis sensitivity and nonlinearity at a level of 0.5 of FS which are comparatively better than already reported devices and commercially available piezoresistive sensors. © 2012 The Institution of Engineering and Technology.

Micro & Nano Letters

Realisation of silicon piezoresistive accelerometer with proof mass-edge-aligned-flexures using wet anisotropic etching

Micro and Nano Systems Letters

A comprehensive review on convex and concave corners in silicon bulk micromachining based on anisotropic wet chemical etching

Journal of Micromechanics and Microengineering

Performance enhancement of a silicon MEMS piezoresistive single axis accelerometer with electroplated gold on a proof mass

Fabrication techniques of convex corners in a (1 0 0)-silicon wafer using bulk micromachining: a review

Journal	Data powered by TypesetLecture Notes in Electrical Engineering Microelectronics, Electromagnetics and Telecommunications
Publisher	Data powered by TypesetSpringer Singapore
ISSN	1876-1100
Open Access	No