Jiahao Zhao

The Enhancement of

In this paper, we demonstrate an effective way of annealing in vacuum to enhance the -Factor of planar spiral inductors for RF applications. The impact on the enhancement of the Q has been quantitatively analyzed using an equivalent circuit model. For the on-top type spiral inductor on silicon substrates, the peak value of Q-Factor is increased by 32.4% and 45.9% after annealing at 250degC and 350degC, respectively. The annealed copper coil exhibits an observable reduction in cavity defects, leading to a significant -enhancement due to the improvement in conductivity. A decrease in substrate resistance for an annealed inductor is also observed, which has a negative influence on enhancement. However, the final increment of the Q-Factor by annealing proves that the contribution of the copper coil is dominant.

Q

Super-resolution technology has been applied to overcome the optical diffraction limit in recent years. In this work, optical super resolution based on Sb films has been studied. Experimental results show that the amorphous Sb–SR will considerably concentrate the energy into the center of the laser beam, while the crystal Sb–SR will not. Considering Sb as a semiconductor with a small energy gap, a three-order nonlinear response of surface plasmons is deduced to explain the phenomenon. Estimation is made and the calculated results are in agreement with the experimental results.

-Factor of Planar Spiral Inductor With Low-Temperature Annealing

A self-actuating and detecting (SAD) circuit loop that drives a micro-cantilever in a gas sensor, in which the resonance frequency shifting of the beam is monitored to detect its mass change caused by adsorption of certain gas molecules, is presented. The loop cannot only drive the cantilever but also trace the fundamental resonance frequency shift of the beam. The motivation of the SAD circuit is simplifying structure and process of the microbeam. This paper presents simulation and experiments of the mechanical resonance of the microbeam and resonance of the electric signal in the SAD loop. The relations between the two resonance frequencies are discussed and analyzed. While the beam is driven in resonating mode, the resonance frequency shift of the signal in the SAD circuit is approximately equal to the mechanical resonant frequency shift of the cantilever. The frequency resolution of the SAD with the microbeam is 0.6-0.7 Hz in our work, and theoretical measurement range of the system is 18750 Hz.

Approach for imaging optical super-resolution based on Sb films

MEMS relays/switches have been some of the most interesting hotspots in all kinds of MEMS devices for decades. Electrostatic actuation is the most popular actuation principle. A novel in-plane electrostatic comb-drive actuator for MEMS relays/switches was designed and fabricated. Double-tilt comb fingers and tilted parallelogram beams were proposed to achieve the requirements of MEMS relays/switches. The restoring force curve, actuation force curve, and pull-in voltage were measured. Double-tilt fingers were found to have a larger actuation force than traditional rectangular fingers, and the pull-in voltage was decreased by 25% by replacing rectangular fingers with double-tilt fingers. In addition, tilted parallelogram beams provided a convex upward restoring force curve, which was more suitable for MEMS relays/switches than the conventional force curve.

Resonating Frequency of a SAD Circuit Loop and Inner Microcantilever in a Gas Sensor

Micro-cantilever sensors for mass detection using resonance frequency have attracted considerable attention over the last decade in the field of gas sensing. For such a sensing system, an oscillator circuit loop is conventionally used to actuate the micro-cantilever, and trace the frequency shifts. In this paper, gas experiments are introduced to investigate the mechanical resonance frequency shifts of the micro-cantilever within the circuit loop(mechanical resonance frequency, MRF) and resonating frequency shifts of the electric signal in the oscillator circuit (system working frequency, SWF). A silicon beam with a piezoelectric zinc oxide layer is employed in the experiment, and a Self-Actuating-Detecting (SAD) circuit loop is built to drive the micro-cantilever and to follow the frequency shifts. The differences between the two resonating frequencies and their shifts are discussed and analyzed, and a coefficient α related to the two frequency shifts is confirmed.

Electrostatic comb-drive actuator for MEMS relays/switches with double-tilt comb fingers and tilted parallelogram beams

Ag-Si3N4 composite films with metal fractions of 20% and 33% were prepared by magnetron sputtering. The Ag particles inside the composite films were less than 5 nm in radius. The optical absorption and near-field enhancement properties of the composite films were measured. On the plots of optical absorption, the extra absorption was observed as well as the surface plasmon resonance absorption. The intensity of the extra absorption depended on the particle size and metal fraction. Moreover, the composite films with higher extra absorption had better near-field enhancement properties. These phenomena were possibly related with the interaction between Ag particles in composite films.

Investigation of the Frequency Shift of a SAD Circuit Loop and the Internal Micro-Cantilever in a Gas Sensor

A micro-beam of a creative smart resonating gas sensor with a self-actuating and detecting (SAD) system is presented. The smart SAD sensor, in which the resonance frequency shifting of the MEMS cantilever is monitored to probe its mass change caused by adsorption of certain gas molecules, has never need exclusive detection circuits and instruments, and the micro-beam has never need additional detective MEMS structure consequently. Some design rules of the more compact micro-beam has been obtained by computer simulation analysis and related discusses. Some electrostatic driving MEMS beam has been fabricated by surface silicon micromachining and sacrificial layer process with low cost, and tested by laser vibration-meter system. An improvement of the micro-beam is introduced by comparison study of the computer simulation results and testing results of the fabricated beam.

Influence of the interaction between metal particles on optical properties of Ag-Si 3 N 4 composite films. I. Experiment

The interaction between metal particles was calculated based on the discrete dipole method. The calculated results revealed that the multiple interactions in a collection of metal particles are dominated by the interaction between the neighboring particles. Thus, a two-particle approximation was deduced and applied to estimate the optical absorption and near-field enhancement property of Ag-Si3N4 composite films. The calculated results indicated that the interaction between Ag particles will induce extra absorption near the surface plasmon resonance peak and improve the near-field enhancement property of composite films. Calculated results were consistent with the experimental results.

Improvement of a micro-beam in a smart gas sensor with resonating mechanism

On-line and on-wafer characterizations of mechanical properties of Micro-Electro-Mechanical-System (MEMS) with efficiency are very important to the mass production of MEMS foundry in the near future. However, challenges still remain. In this paper, we present an in-plane vibration characterizing method for MEMS comb using optical Fourier transform (OFT). In the experiment, the intensity distribution at the focal plane was captured to characterize the displacement of the vibrator in the MEMS comb structure. A typical MEMS comb was tested to verify the principle. The shape and the movement of MEMS comb was imitated and tested to calibrate the measurement by using a spatial light modulator (SLM). The relative standard deviations (RSD) of the measured displacements were better than 5%, where the RSD is defined as the ratio of the standard deviation to the mean. It is convinced that the presented method is feasible for on-line and on-wafer characterizations for MEMS with great convenience, high efficiency and low cost.

Influence of the interaction between metal particles on optical properties of Ag-Si3N4 composite films. II. Two-particle approximation.

Magnetic medium is an effective approach to RF planar magnetic inductor confirmed by computer simulations. The magnetic inductor was designed and fabricated using novel Permalloy-SiO2 (PS) granular film as magnetic core. The granular film shows excellent soft magnetic properties and high resistivity by adjusting the composition and microstructure. The inductor with PS granular film exhibits a higher L than air-core inductor and a considerable Q above 10. The anisotropy of the granular film generated in deposition process make the magnetic inductor has a very high self-resonance frequency peak