scholarly journals A Temperature-Compensated Single-Crystal Silicon-on-Insulator (SOI) MEMS Oscillator with a CMOS Amplifier Chip

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 559 ◽  
Author(s):  
Mohammad Islam ◽  
Ran Wei ◽  
Jaesung Lee ◽  
Yong Xie ◽  
Soumyajit Mandal ◽  
...  

Self-sustained feedback oscillators referenced to MEMS/NEMS resonators have the potential for a wide range of applications in timing and sensing systems. In this paper, we describe a real-time temperature compensation approach to improving the long-term stability of such MEMS-referenced oscillators. This approach is implemented on a ~26.80 kHz self-sustained MEMS oscillator that integrates the fundamental in-plane mode resonance of a single-crystal silicon-on-insulator (SOI) resonator with a programmable and reconfigurable single-chip CMOS sustaining amplifier. Temperature compensation using a linear equation fit and look-up table (LUT) is used to obtain the near-zero closed-loop temperature coefficient of frequency (TCf) at around room temperature (~25 °C). When subject to small temperature fluctuations in an indoor environment, the temperature-compensated oscillator shows a >2-fold improvement in Allan deviation over the uncompensated counterpart on relatively long time scales (averaging time τ > 10,000 s), as well as overall enhanced stability throughout the averaging time range from τ = 1 to 20,000 s. The proposed temperature compensation algorithm has low computational complexity and memory requirement, making it suitable for implementation on energy-constrained platforms such as Internet of Things (IoT) sensor nodes.

Author(s):  
N. Lewis ◽  
E. L. Hall ◽  
A. Mogro-Campero ◽  
R. P. Love

The formation of buried oxide structures in single crystal silicon by high-dose oxygen ion implantation has received considerable attention recently for applications in advanced electronic device fabrication. This process is performed in a vacuum, and under the proper implantation conditions results in a silicon-on-insulator (SOI) structure with a top single crystal silicon layer on an amorphous silicon dioxide layer. The top Si layer has the same orientation as the silicon substrate. The quality of the outermost portion of the Si top layer is important in device fabrication since it either can be used directly to build devices, or epitaxial Si may be grown on this layer. Therefore, careful characterization of the results of the ion implantation process is essential.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1118
Author(s):  
Yuan Tian ◽  
Yi Liu ◽  
Yang Wang ◽  
Jia Xu ◽  
Xiaomei Yu

In this paper, a polyimide (PI)/Si/SiO2-based piezoresistive microcantilever biosensor was developed to achieve a trace level detection for aflatoxin B1. To take advantage of both the high piezoresistance coefficient of single-crystal silicon and the small spring constant of PI, the flexible piezoresistive microcantilever was designed using the buried oxide (BOX) layer of a silicon-on-insulator (SOI) wafer as a bottom passivation layer, the topmost single-crystal silicon layer as a piezoresistor layer, and a thin PI film as a top passivation layer. To obtain higher sensitivity and output voltage stability, four identical piezoresistors, two of which were located in the substrate and two integrated in the microcantilevers, were composed of a quarter-bridge configuration wheatstone bridge. The fabricated PI/Si/SiO2 microcantilever showed good mechanical properties with a spring constant of 21.31 nN/μm and a deflection sensitivity of 3.54 × 10−7 nm−1. The microcantilever biosensor also showed a stable voltage output in the Phosphate Buffered Saline (PBS) buffer with a fluctuation less than 1 μV @ 3 V. By functionalizing anti-aflatoxin B1 on the sensing piezoresistive microcantilever with a biotin avidin system (BAS), a linear aflatoxin B1 detection concentration resulting from 1 ng/mL to 100 ng/mL was obtained, and the toxic molecule detection also showed good specificity. The experimental results indicate that the PI/Si/SiO2 flexible piezoresistive microcantilever biosensor has excellent abilities in trace-level and specific detections of aflatoxin B1 and other biomolecules.


2019 ◽  
Vol 5 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Svetlana P. Kobeleva ◽  
Ilya M. Anfimov ◽  
Vladimir S. Berdnikov ◽  
Tatyana V. Kritskaya

Electrical resistivity distribution maps have been constructed for single crystal silicon wafers cut out of different parts of Czochralski grown ingots. The general inhomogeneity of the wafers has proven to be relatively high, the resistivity scatter reaching 1–3 %. Two electrical resistivity distribution inhomogeneity types have been revealed: azimuthal and radial. Experiments have been carried out for crystal growth from transparent simulating fluids with hydrodynamic and thermophysical parameters close to those for Czochralski growth of silicon single crystals. We show that a possible cause of azimuthal electrical resistivity distribution inhomogeneity is the swirl-like structure of the melt under the crystallization front (CF), while a possible cause of radial electrical resistivity distribution inhomogeneity is the CF curvature. In a specific range of the Grashof, Marangoni and Reynolds numbers which depend on the ratio of melt height and growing crystal radius, a system of well-developed radially oriented swirls may emerge under the rotating CF. In the absence of such swirls the melt is displaced from under the crystallization front in a homogeneous manner to form thermal and concentration boundary layers which are homogeneous in azimuthal direction but have clear radial inhomogeneity. Once swirls emerge the melt is displaced from the center to the periphery, and simultaneous fluid motion in azimuthal direction occurs. The overall melt motion becomes helical as a result. The number of swirls (two to ten) agrees with the number of azimuthally directed electrical resistivity distribution inhomogeneities observed in the experiments. Comparison of numerical simulation results in a wide range of Prandtl numbers with the experimental data suggests that the phenomena observed in transparent fluids are universal and can be used for theoretical interpretation of imperfections in silicon single crystals.


2020 ◽  
pp. 100107
Author(s):  
L.G. Michaud ◽  
E. Azrak ◽  
C. Castan ◽  
F. Fournel ◽  
F. Rieutord ◽  
...  

Author(s):  
Wenjun Liu ◽  
Mehdi Asheghi ◽  
K. E. Goodson

Simulations of the temperature field in Silicon-on-Insulator (SOI) and strained-Si transistors can benefit from experimental data and modeling of the thin silicon layer thermal conductivity at high temperatures. This work presents the first experimental data for 20 and 100 nm thick single crystal silicon layers at high temperatures and develops algebraic expressions to account for the reduction in thermal conductivity due to the phonon-boundary scattering for pure and doped silicon layers. The model applies to temperatures range 300–1000 K for silicon layer thicknesses from 10 nm to 1 μm (and even bulk) and agrees well with the experimental data. In addition, the model has an excellent agreement with the predictions of thin film thermal conductivity based on thermal conductivity integral and Boltzmann transport equation, although it is significantly more robust and convenient for integration into device simulators. The experimental data and predictions are required for accurate thermal simulation of the semiconductor devices, nanostructures and in particular the SOI and strained-Si transistors.


1996 ◽  
Vol 438 ◽  
Author(s):  
S. J. Morris ◽  
B. Obradovic ◽  
S.-H. Yang ◽  
A. F. Tasch ◽  
L. Rubin

AbstractAn electronic stopping power model for boron, arsenic, and phosphorus ion implantation into single-crystal Si is reported over the energy range from a few keV to several MeV, for both offand on-axis implant angles relative to the <100> crystallographic direction. Combined with previously developed models for damage accumulation, this model allows physically-based simulation of 3-D profiles over an extremely wide range of implant conditions. In particular, this allows modeling of MeV implants which are being used more and more frequently.


1992 ◽  
Vol 283 ◽  
Author(s):  
Akif Sultan ◽  
Shubneesh Batra ◽  
Melvyn Lobo ◽  
Keunhyung Park ◽  
Sanjay Banerjee

ABSTRACTIn the present study we have modeled the diffusion of boron in single crystal silicon from an ion-implanted polysilicon film deposited on a single crystal silicon substrate. Modeling has been done for both BF2 and boron implants in the polysilicon layer. A new phenomenological model for a diffusivity has been implemented in the PEPPER simulation program using an effective concentration-dependent diffusivity approach. The effective diffusivities of boron in single crystal silicon have been extracted using Boltzmann-Matano analysis. The modeling has been implemented for a wide range of furnace anneal conditions (800°C to 950°C, from 30 min. to 6 hours), and implant conditions (BF2 doses varied from 5×1015 to 2×10'16 cm-2 at 70 keV, boron dose of 5×1015 cm-2 at 20 keV).


2000 ◽  
Author(s):  
John M. Maloney ◽  
Don L. DeVoe ◽  
David S. Schreiber

Abstract Thermal actuators that deflect laterally by resistive heating have been fabricated in single crystal silicon (SCS) by deep reactive ion etching (DRIE). With heights of 50 μm, these high-aspect actuators produce significantly larger forces than similar polysilicon devices. Problems with stiction are also avoided through the use of silicon-on-insulator (SOI) technology. An analytical model is applied to U-beam and V-beam actuator shapes fabricated on SOI wafers. The electrothermal component of the analysis uses an axial conduction model to predict temperature distribution; the thermomechanical component employs elastic beam theory to calculate deflection due to thermal strain. Experimental results are compared to analytical predictions. Deflections of 29 μm for a 1200 μm long, 12 μm wide V-beam actuator were observed, corresponding to a predicted force of 7.6 mN.


1984 ◽  
Vol 33 ◽  
Author(s):  
P. Zorabedian ◽  
T. I. Kamins

ABSTRACTTwo scanning methods for laterally-seeded recrystallization of striped silicon-on-insulator/seed structures with an elliptical laser beam are discussed. One method requires repeated remelting of the silicon film and is controlled by the temperature of the substrate, which is locally heated by the beam. This method results in very few defects and single-crystal silicon-on-insulator stripes up to 50 μm wide. The second method involves little remelting and is primarily controlled by the lateral offset of the beam with respect to the stripes. Single-crystal silicon-on-insulator stripes up to 40 μm wide have been obtained, with defects consisting primarily of stacking faults and twins, as well as some grain boundaries. These defects show little effect on MOS transistor leakage current.


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