Gary O'Brien
Bosch
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Publication
Featured researches published by Gary O'Brien.
international conference on micro electro mechanical systems | 2013
Sarah H. Nitzan; Chae Hyuck Ahn; T.-H. Su; Mo Li; Eldwin J. Ng; Shasha Wang; Z. M. Yang; Gary O'Brien; Bernhard E. Boser; Thomas W. Kenny; David A. Horsley
We present a 0.6 mm diameter, 20 μm thick epitaxially-sealed polysilicon disk resonator gyro (DRG). High Q (50,000) combined with electrostatic mode-matching and closed-loop quadrature null performed by dedicated electrode sets enables a scale-factor of 0.286 mV/(°/s) and Angle Random Walk (ARW) of 0.006 (°/s)/√Hz. Without precise control of temperature, the minimum Allan deviation is 3.29 °/hr.
international conference on micro electro mechanical systems | 2013
Chia-Fang Chiang; Andrew B. Graham; Brian J. Lee; Chae Hyuck Ahn; Eldwin J. Ng; Gary O'Brien; Thomas W. Kenny
Temperature and package stress induced errors pose a challenging obstacle for improving accuracy of strain-based resonant pressure sensors. This paper presents a multiple sensor solution where three resonators were built under a shared pressure sensor diaphragm. By manipulating the anchoring scheme and the location of the resonators, temperature and stress signals can be independently captured and used to compensate for the errors in the pressure signal. After compensation, the pressure sensor showed a 20× reduction in temperature dependency and a 2× reduction in stress dependency.
international conference on micro electro mechanical systems | 2012
Chia-Fang Chiang; Andrew B. Graham; Gary O'Brien; Thomas W. Kenny
In this paper, we present a capacitive absolute pressure sensor co-fabricated with a MEMS resonator using an improved epitaxial polysilicon encapsulation process. The process features insensitivity to timed hydrofluoric acid etch variation when releasing structures via sacrificial silicon dioxide. Moreover, the process enables fabrication of structures to drive/sense in both lateral (x, y) and vertical (z) directions, providing a powerful fabrication platform for sensor integration on either bulk silicon or SOI wafer substrates.
international conference on micro electro mechanical systems | 2015
Eldwin J. Ng; Yushi Yang; Vu A. Hong; Chae Hyuck Ahn; David B. Heinz; Ian B. Flader; Yunhan Chen; Camille L. M. Everhart; Bongju Kim; Renata Melamud; Rob N. Candler; Matthew A. Hopcroft; James C. Salvia; Shingo Yoneoka; Andrew B. Graham; Manu Agarwal; Matthew W. Messana; Kuan-Lin Chen; Hyung Kyu Lee; Shasha Wang; Gaurav Bahl; V. Qu; Chia-Fang Chiang; Thomas W. Kenny; Aaron Partridge; Markus Lutz; Gary Yama; Gary O'Brien
Research on MEMS Resonators began over 50 years ago. In just the last 10 years, there has been a series of important technological developments, and (finally!) success at commercialization. The presentation will highlight some key milestones along this path, describe some of the critical technology steps, and outline some of the important non-technological events within SiTime - all of these factors contributed to the successful outcome.
international conference on micro electro mechanical systems | 2015
David B. Heinz; Vu A. Hong; T.S. Kimbrell; J. Stehle; Chae Hyuck Ahn; Eldwin J. Ng; Yushi Yang; Gary Yama; Gary O'Brien; Thomas W. Kenny
We demonstrate the consistent and manageable nature of surface adhesion and stiction forces in MEMS devices fabricated using the high-temperature epitaxial encapsulation process. In this encapsulation process (commercialized by SiTime), there are no chemical anti-stiction films or getters. Data from more than 2000 test structures with more than 80 design variations from three different fabrication runs were gathered in this study. Surprisingly, the adhesion force is shown to be independent of design geometry. The measured adhesion forces (18-25uN) are small enough for inertial sensors. In addition, we demonstrate anti-stiction bump stops with springs for a sliding contact, which reduce the probability of stiction by over 50%.
international conference on micro electro mechanical systems | 2013
Fabian Purkl; Tim English; Gary Yama; J. Provine; Ashwin Samarao; Ando Feyh; Gary O'Brien; O. Ambacher; Roger T. Howe; Thomas W. Kenny
We report the realization of coalescent free-standing ultra-thin (as thin as 5.5 nm) platinum layers deposited via plasma-enhanced atomic layer deposition and their characterization as an uncooled infrared detector. Such thin platinum thermistors enable a responsivity as high as 2 · 107 V/WA, an estimated noise equivalent temperature difference of 163 mK and thermal time constants on the order of 1 ms.
international conference on solid state sensors actuators and microsystems | 2015
Vu A. Hong; J. Stehle; Chae Hyuck Ahn; David B. Heinz; Gary Yama; Bongsang Kim; Gary O'Brien; Thomas W. Kenny
This paper presents a capacitive X/Y and Z-axis accelerometer, pressure sensor, and resonant thermometer, co-fabricated in a single die using an ultra-clean, high-temperature, wafer-scale, production-compatible encapsulation process. This process is free of bond rings and getter areas, thereby reducing overall die size to a minimum. Utilizing a process that allows for nitride and silicon etch stops, we show that it is possible to design high-sensitivity pressure sensors and accelerometers with very little cross-sensitivity. In addition, remaining sensitivities to environmental effects, such as temperature, can be compensated to reveal a suite of on-chip high-performance sensors that is accurate over temperature. All of this is accomplished in a process similar to current high-volume production processes in industry.
international conference on solid-state sensors, actuators and microsystems | 2011
Chia-Fang Chiang; Andrew B. Graham; Matthew W. Messana; J. Provine; Daniela T. Buchman; Gary O'Brien; Thomas W. Kenny
Unlike a traditional capacitive pressure sensor, which uses the entire deflectable diaphragm as the electrode, this paper proposes the use of reduced electrode area to increase the fractional capacitance change and reduce the devices sensitivity to package stresses. Therefore, in addition to the low temperature sensitivity inherent in capacitive sensing, the proposed pressure sensor helps relax signal conditioning requirements typically associated with capacitive sensor interface circuitry.
Archive | 2012
Andrew B. Graham; Gary Yama; Gary O'Brien
Archive | 2013
Ashwin Samarao; Gary O'Brien; Ando Feyh; Fabian Purkl; Gary Yama