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This paper describes the possibility of the crystalline anisotropic etching of single-crystal silicon using a fully dry etching process. Conventionally, the crystalline anisotropic etching of silicon has been achieved only using specific wet solutions. In the proposed method, the anisotropic etching is made dominant by controlling the etching energy under specific dry etching conditions. The maximum...
We found that an appropriate mixture of SF6, C4F8 and O2 gases in a standard Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE) apparatus achieves crystal orientation dependent etching. The etched shapes after the RIE of silicon wafers with (100), (110), and (111) surface orientation are investigated by the masks with circular openings and isolated pattern. The results of the etching process...
This paper presents the first-ever vertical silicon nanowire array based all-optical pressure sensor. Vertical silicon nanowire arrays with photonic crystal structure, can selectively trap or diffract light, depending on the optical wavelength, nanowire diameter, and nanowire pitch spacing. Here, we realize an all-optical pressure sensor by fabricating controllable vertical silicon nanowire arrays...
We report the theory, design methodology and experiment of an electrostatically actuated silicon-plate Phononic Bandgap (PnBG) crystal architecture. This architecture is a high-order distributed mechanical system comprised of a two-dimensional PnBG crystal which is truncated to finite periodicity and suspended from the substrate utilizing tethers. Electrostatic actuation mitigates the use of piezoelectric...
Current crowding of a micro spring pressure contact under high current is studied. The spring conducts >; 250 mA electrical current between chips, has large mechanical compliance (>; 30 μm) compared to other packaging technologies, and fits in a 180 μm pitch 2d array. At 250 mA and 65°C, daisy chains of 134 spring contacts in a silicon package show stable resistances and hot spot temperature...
A new biaxial silicon resonant accelerometer characterized by a high sensitivity and a low cross-axis sensitivity is presented in this paper. The device allows for the simultaneous measure of acceleration acting along two different axes using two couples of resonating slender beams linked to two couples of flexible beams and to a proof mass. The conceptual scheme used for the biaxial resonant accelerometer...
Silicon is susceptible to fatigue even under inert environment, although it has been believed not to be. This paper presents a brand-new image of the fatigue behavior of silicon obtained using the microtensile method. It is estimated that 25% of polysilicon specimens and 34% of single-crystal silicon will break in about 100 years in a nitrogen atmosphere at room temperature, when subjected to a fatigue...
A new fabrication process, which includes deposition of thin silver film on silicon surface prior to wet etching, is proposed for realizing aligned silicon nanowires with high uniformity, resulting in black nonreflecting silicon surface.
We present the design of a silicon microsystem that utilizes dense, low-power photonic interconnects to enable a highly-compact supercomputer-scale system. We review recent progress in wavelength-division multiplexed, low-power silicon photonic interconnect components and discuss a future roadmap for the technology.
A couple of decade ago when auto engineers decided to increase the voltage level of electrical power system drive, it was the advancement of silicon technology supporting their dream. Today the power electronics circuits play an important role in the success of electric, hybrid and fuel cell vehicles. Typical power electronics circuits in hybrid vehicles include electric motor drive circuits and DC/DC...
A hybrid III-V silicon evanescent laser with sidewalled gratings as the feedback element, and having 60% waveguide confinement is proposed. The device is fabricated using e-beam lithography, and low-temperature plasma assisted direct bonding.
This paper shows improved phase-noise performance of MEMS oscillators when the sustaining amplifier operates a lateral bulk acoustic wave AlN-on-Si resonator in the nonlinear regime. An empirical exponential-series-based model that closely describes the phase noise in nonlinearity is presented, reflecting the increased resonator filter order and the reduced amplifier flicker-noise contribution. An...
This work demonstrates the self-Q enhancement capability of micro/nanomechanical thermal-piezoresistive resonators. Due to the existence of an internal feedback mechanism in one-port thermally actuated electromechanical resonators, such devices can compensate their mechanical energy loss by turning part of the electrical energy absorbed from their bias source into mechanical energy. This can lead...
We report here on high resonance frequency AFM probes based on MEMS bulk mode resonators. They consist on silicon ring resonators with capacitive transducers vibrating in the in-plane elliptic mode. Nano-tips placed at the maximum of vibration are fabricated in batch process. After electrical and optical characterizations, chips supporting the resonator and the prominent tip are extracted from the...
This paper demonstrates a dual-mode (DM) oscillator which simultaneously excites the fundamental and third-order modes of a micromachined, piezo-on-silicon bulk acoustic wave (BAW) resonator for real-time self-temperature measurement. By concurrently measuring the temperature coefficient of frequency (TCF) at 30 MHz (f1) and 87 MHz (f3), a beat frequency (fb) with TCF of 162 ppm/°C is extracted. Phase...
We studied the effect of excess carriers, temperature and current on acoustic waves in silicon delay lines. Heat and excess carriers reduce the acoustic velocity by respectively reducing the Young's modulus and through the deformation potential. Electrical current, on the other hand, can increase the acoustic velocity depending on their drift velocity. In addition to current, acoustic waves can also...
The single-shot interferometric imaging of normal mode dynamics in MEMS resonators, oscillating in the radio frequency (rf) regime, is demonstrated by synchronous imaging with a pulsed nanosecond laser. Profiles of mechanical modes in suspended silicon and graphene thin-film structures, and their extracted equilibrium profiles, are measured through nondestructive all-optical Fabry-Perot reflectance...
This paper reports a 3-dimensional (3D) micro-optical coupling system for improving coupling efficiency in the Littrow configured micro-electro-mechanical system (MEMS) tunable lasers. In the coupling system, an optical fiber acts as a rod lens for light convergence in the vertical plane, while a deep-etched silicon parabolic mirror confines the light in the horizontal plane. Compared with previous...
A measurement system was newly developed to evaluate the mechanical properties of micro-sized materials at very low temperature ranging from -130°C to room temperature, using liquid nitrogen cooling. In this work, we conducted the fracture toughness tests of single crystal silicon films with thicknesses of about 1 μm at low temperature and found the temperature dependence on the fracture toughness,...
We have developed and characterized a novel 3D flexible parylene-based microelectrode array (MEA) with silicon tips, which combines advantages of the rigid 3d electrode and the flexible substrate. The impedance of solid 3D MEA in PBS solution is smaller than that of the planar and hollow 3D MEA. Further tests indicate that the solid 3D MEA has better penetrating performance, and retains previous structure...
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