Graduate Research Assistant
Mechanical Engineering Department,
Ph.D. (ME) Stanford University, 2004-Present
M.S. (ME) Stanford University, 2002-2004
B.Tech. (ME) Indian Institute of Technology Madras, Chennai, India, 1998-2002
Office: 530-101 | Phone: (650) 804-0834 |
723-7657 | Email: firstname.lastname@example.org
MEMS and microsystems, mechatronics, Nano technology
control systems, Bio-medical devices.
Thomas W Kenny, Department of Mechanical Engineering
Wafer scale encapsulated MEMS Gyros
The goal of the present work is to fabricate a high sensitivity inertial sensor with a
reasonably good bandwidth using the thin wafer scale encapsulation technique. Packaging
is an important step towards commercialization of the device and we plan to use thin wafer
scale encapsulation technique developed previously in our group to package these devices.
The silicon micro machined gyroscope will be fabricated on SOI wafers using Bosch DRIE etching
techniques, which has been previously demonstrated in the fabrication of accelerometers.
The encapsulation of the device can be carried out using LTO or epitaxial sealing in order to
provide a high vacuum inside the device chamber. The advantages offered by this technique are
the reduction in area of the die and thus less silicon surface is wasted. In addition to this
the encapsulation technique helps in creating a vacuum inside the micro device, which reduces
the damping effects and hence increases the quality factor Q of the gyro thus increasing the sensitivity.
The project is supported by Defence Science Organisation (DSO), Singapore.
Wafer scale encapsulated miniature MEMS piezoresistive accelerometers
MEMS accelerometers have been around since late 1970's. Efforts have been ongoing to reduce the size of
MEMS accelerometers to a range where they can be used for various Bio-medical applications like measurement
of heart wall or to characterize lumbar spinal manipulation. The same sensor can be used in cochlear and
middle ear implant. Important criteria for using MEMS devices in sucg applications is reducing the size of the
device. This has to be done by reducing the packaging material as the sensor element does not scale well with
sensor parameters. The over all size of the MEMS accelerometer is reduced using wafer scale encapsulation process.
In this method the device is sealed inside the wafer by deposition of a thin layer of epitaxial silicon.
High speed acoustic separation of particles in microchannel using ultrasound
A standing wave is generated in a microchannel containing particles suspended in a fluid resulting in the particles
experiencing acoustic radiation pressure. Acoustic radiation pressure is used to collect all the particle in a micro channel
at the node using standing waves.Depending on the density and compressibility of the medium and particle the particle can
either be collected at the node or the anti-node. In order to seperate two particles in a fluid flow, it is necessary to
exploit the differencein physical property between the two. Here we make use of difference in accoustic radiation felt by
particles of different sizes in order to seperate them.In a standing wave the acoustic radiation pressure depends on volume
of a sperical particle. This means that as long as other physical properties are similar larger particles will move towards the node faster.
Thomas W Kenny, Department of Mechanical Engineering)
Go to Top
- Ayanoor-Vitikkate, V; Chen, K-L; Park, WT; Kenny TW; "Development of a process for wafer scale
encapsulation of devices with very wide trenches". ASME IMECE 2006, Chicago (In print).
- Ayanoor-Vitikkate, V; Chen, K-L; Park, WT;Yama, G; Kenny TW; "Wafer Scale Encapsulation of wide
Gaps using oxidation of sacrificial Beams". IEEE IEMT 2006, Petaling Jaya, Malaysia.
- Woo-Tae Park; Partridge, A.; Candler, RN; Ayanoor-Vitikkate, V.; Yama, G.; Lutz, M.; Kenny, TW
"Encapsulated submillimeter piezoresistive accelerometers". Source: Journal of Microelectromechanical
Systems; June 2006; v.15, no.3, p.507-514
- Li, Holden; Vitikkate, Vipin; Kenny, Thomas. "High speed particles separation using ultrasound for
lab-on-chip application". Source: American Society of Mechanical Engineers, Micro-Electro Mechanical
Systems Division, (Publications) MEMS; 2004; p.487-490
- Park, Woo-Tae; Candler, Rob N.; Ayanoor-Vitikkate, Vipin; Lutz, Markus; Partridge, Aaron; Yama, Gary; Kenny, Thomas W.
"Fully encapsulated sub-millimeter accelerometers." Source: Proceedings of the IEEE International Conference on
Micro Electro Mechanical Systems (MEMS); 2005; p.347-350
- Li, Holden; Vitikkate, Vipin; Kenny, TW; "Study of high speed acoustic separation in micro channels using u-PIV."
8th International Conference on Miniaturized Systems for Chemistry and Life Sciences. Sept 26-30, 2004, Malmo, Sweden.
- Woo-Tae Park; O'Connor, KN; Mallon, JR, Jr.; Maetani, T.; Candler, RN; Ayanoor-Vitikkate V; Roberson, JB; Puria, S.; Kenny, TW
"Sub-mm encapsulated accelerometers: a fully implantable sensor for cochlear implants." Source: TRANSDUCERS '05. The 13th
International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers, 5-9 June 2005, Seoul,
South Korea; p.109-12 Vol. 1
Go to Top
- Stanford Nano Facility
- Centre for Integrated Systems
- Micro Structures & sensors Lab
- Mechanical Engineering
Last updated February 21, 2007