Fabrication and Test of 3C-SiC Electrostatic Resonators

2007 ◽  
Vol 556-557 ◽  
pp. 949-952
Author(s):  
Marcel Placidi ◽  
Phillippe Godignon ◽  
Jaume Esteve ◽  
Narcis Mestres ◽  
Gabriel Abadal
Keyword(s):  
Sacrificial Layer ◽  
Ambient Condition ◽  
Wet Etching ◽  
Test Results ◽  
Si Substrate ◽  
Capacitive Current ◽  
Step Process ◽  
Electrostatically Actuated ◽  
Icp Etching ◽  
Resonance Frequencies

Silicon Carbide has proven its relevance for various MEMS and sensors devices applications. This paper presents the fabrication and the first test results of 3C-SiC electrostatic resonators actuated by applying a combination of AC and DC voltages. The recipe used for the fabrication has taken the advantage of the starting material, 3C-SiC grown on Si, which allows us to use the Si substrate as sacrificial layer to release the structures. Resonators have been fabricated by a two-step process, combining RIE ICP etching with HF wet etching. Resonators have been successfully electrostatically actuated in air-ambient condition. The resonance frequencies were clearly identified, although capacitive current created by actuation was not detected.

Plane Wave Resonance in the Tire Air Cavity as a Vehicle Interior Noise Source

1995 ◽  
Vol 23 (1) ◽  
pp. 2-10 ◽  
Author(s):  
J. K. Thompson
Keyword(s):  
Closed Form Solution ◽  
Form Solution ◽  
Interior Noise ◽  
Cavity Resonance ◽  
Test Results ◽  
Vehicle Interior ◽  
Air Cavity ◽  
Vehicle Interior Noise ◽  
Wave Resonance ◽  
Resonance Frequencies

Abstract Vehicle interior noise is the result of numerous sources of excitation. One source involving tire pavement interaction is the tire air cavity resonance and the forcing it provides to the vehicle spindle: This paper applies fundamental principles combined with experimental verification to describe the tire cavity resonance. A closed form solution is developed to predict the resonance frequencies from geometric data. Tire test results are used to examine the accuracy of predictions of undeflected and deflected tire resonances. Errors in predicted and actual frequencies are shown to be less than 2%. The nature of the forcing this resonance as it applies to the vehicle spindle is also examined.

MEMS Microresonators Based on Nanocrystalline Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
J. Gaspar ◽  
T. Adrega ◽  
V. Chu ◽  
J. P. Conde
Keyword(s):  
Energy Dissipation ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Quality Factors ◽  
Electrostatically Actuated ◽  
Glass Substrates ◽  
Boron Doped ◽  
Resonance Frequencies ◽  
Geometrical Dimensions

ABSTRACTThis paper describes the fabrication and characterization of thin-film nanocrystalline silicon microresonators processed at temperatures below 110°C on glass substrates. The microelectromechanical structures consist of surface micromachined bridges of boron-doped hydrogenated nanocrystalline silicon (p+-nc-Si:H) deposited at 100°C by hot-wire chemical vapor deposition (HWCVD). The microbridges, which are suspended over an Al gate electrode, are electrostatically actuated and the mechanical resonance is detected in vacuum using an optical setup. The resonance frequency and energy dissipation in p+-nc-Si:H based resonators are studied as a function of the geometrical dimensions of the microstructures. Resonance frequencies between 700 kHz and 36 MHz and quality factors as high as 2000 are observed. A Young's modulus of 160 GPa for the structural bridge film is extracted from the experimental data using an electromechanical model and the main intrinsic energy dissipation mechanisms in nc-Si:H microresonators are discussed.

Study of self-actuated screen-printed PZT-cantilevers

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000105-000110
Author(s):  
Riadh LAKHMI ◽  
Christophe CASTILLE ◽  
Hélène DEBEDA ◽  
Mario MAGLIONE ◽  
Claude LUCAT
Keyword(s):  
Screen Printing ◽  
Sintering Temperature ◽  
Sacrificial Layer ◽  
Longitudinal Vibration ◽  
Ferroelectric Ceramics ◽  
Mechanical Pressure ◽  
Bending Mode ◽  
Resonance Frequencies ◽  
Cantilever Structure ◽  
Screen Printed

Usually, resonating cantilevers come from silicon technology and are generally activated with pure bending mode. In this work, we suggest to combine high sensitive cantilever structure with full self-actuated piezoelectric thick-film for high electrical-mechanical coupling. This cantilever is realized through the screen-printing deposition associated with a sacrificial layer. The beam part of the cantilever is composed of a PZT layer between two gold electrodes. Optimum performances of ferroelectric ceramics strongly rely on their composition and microstructure which imply generally the use of mechanical pressure and very high sintering temperature. These conditions are not compatible with the screen-printing process. As already shown with ceramics, addition of eutectic composition Li2CO3-CuO-Bi2O3 or borosilicate glass-frit to PZT powder and application of isostatic pressure, the sintering temperature of cantilevers may be decreased. Screen-printed piezoelectric samples are thus fired at 850°C, 900°C and 950°C. SEM analyses show the densification of the microstructure while increasing the sintering temperature. Electrical and mechanical characterizations are then achieved after poling the self-actuated cantilevers of different dimensions. In addition to the bending mode observed with a vibrometer, we pointed out other resonances related to the piezoelectric properties of the PZT cantilevers. Indeed, the three first orders of “in-plane” 31-longitudinal vibration mode and the first order “out-of-plane” 33-thickness resonance mode are revealed. The resonance frequencies deduced from analytical modeling are linked to the cantilever dimensions and thus confirm the experimental results. The piezoelectric parameters of PZT cantilevers approach those of ceramics. Quality factors of 300 to 400 associated to the unusual 31-longitudinal mode make self-actuated screen-printed PZT cantilevers good candidates for detection in liquid and gaseous media.

Experimental Evaluation of Evaporative Cooler Using Agro Materials

2015 ◽  
Vol 23 (04) ◽  
pp. 1550028 ◽  
Author(s):  
R. Ramkumar ◽  
M. Kesavan ◽  
A. Ragupathy
Keyword(s):  
Ambient Condition ◽  
Experimental Results ◽  
Test Results ◽  
Test Rig ◽  
Air Velocity ◽  
Different Types ◽  
Saturation Efficiency ◽  
Evaporative Cooler ◽  
Luffa Sponge ◽  
Efficiency Improve

The purpose of the study is to investigate the direct evaporate cooler in hot and humid regions with two different types of agro-based materials. In our experimental study, the locally available agro materials luffa (Sponge Gourd), zizanioides (Vetiver) were used with various thickness and the experimental results were compared with mathematical values. The operating parameters of pad thickness, air velocity, were changed and the performance of the cooler was analyzed. A test rig was designed and fabricated to collect experimental data. The performance of the evaporative cooler was evaluated based on the ambient condition. The analysis of the data indicated that cooling saturation efficiency improve with decrease of air velocity and higher pad thickness. It was shown that zizanioides-based pad with 160[Formula: see text]mm thickness has the higher performance (88%) at 4.5[Formula: see text]m/s air velocity in comparison with luffa pad materials. The experimental results of outlet air temperature and number of transfer units (NTU) were compared with mathematical model. The test results were within the limit of 15% and 10% to mathematical values.

Study on the Etching Technique of Non-Photosensitive Polyimide

2015 ◽  
Vol 645-646 ◽  
pp. 163-168
Author(s):  
Rui Lei ◽  
Wei Guo Liu ◽  
Chang Long Cai ◽  
Shun Zhou ◽  
Jing Nie ◽  
...  
Keyword(s):  
Bias Voltage ◽  
Sacrificial Layer ◽  
Dry Etching ◽  
Wet Etching ◽  
Etching Process ◽  
Good Effect ◽  
Floating Structure ◽  
Etching Technique ◽  
Layer Material ◽  
Etching Effect

Polyimide is often used as a sacrificial layer material to make floating structure. Polyimide is also divided into photosensitive and non-photosensitive type; photosensitive polyimide currently has more negative photoresist and poor performance in many ways. Compared with photosensitive polyimide, the non-photosensitive type has low stress, stable performance and other advantages, so non-photosensitive polyimide has been chosen as a sacrificial layer material. To achieve the graphical function and release sacrificial layer, A deeply research was made in this dissertation makes on wet etching and dry etching. By controlling the wet etching process of prebake condition, exposure and developing time, and oxygen dry etching process of etching power, bias voltage and other key process parameters, a good sacrificial layer graph and etching effect have been got. Finally, it can be concluded that when the prebake conditions for 105°C, 8min and times of exposure and developing were 11s and 29s, the non-photosensitive polyimide wet etching effect is the best; when the etching power is 1000w, an oxygen flux rate is 50sccm, the reaction pressure is 30mTorr, the bias voltage is 140v, oxygen dry etching has a good effect.

FABRICATION OF MICRO PROBE-TYPE ELECTRODES FOR MICROELECTRO-CHEMICAL MACHINING USING MICROFABRICATION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2639-2644 ◽  
Author(s):  
W. B. PARK ◽  
J. H. CHOI ◽  
C. W. PARK ◽  
G. M. KIM ◽  
H. S. SHIN ◽  
...  
Keyword(s):  
Metal Layer ◽  
Electrical Contacts ◽  
Wet Etching ◽  
Probe Type ◽  
Test Results ◽  
Steel Mold ◽  
Lift Off

In this study, the mass fabrication of microelectrode tools for microelectrochemical machining (MECM) was studied using microfabrication processes. The cantilever type geometry of microelectrodes was defined by photolithography processes, and metal patterns were made for electrical contacts. Various fabrication processes were studied for the fabrication of microelectrode tools, such as wet etching, lift-off, and electroforming for metal layer patterning. MECM test results showed feasibility of the fabricated electrode tools. The microfabricated electrodes can be used as micromachining tools for various electrical micromachining of steel mold and parts of microdevices.

Fabrication of Anodic Alumina Templates on Ti/Si Substrate and Preparation of Cu Nanorods by Electrochemical Process

2014 ◽  
Vol 1024 ◽  
pp. 27-30
Author(s):  
Khaled M. Chahrour ◽  
Naser M. Ahmed ◽  
M. Roslan Hashim ◽  
Nezar Gassem Elfadill
Keyword(s):  
Pore Diameter ◽  
Electrochemical Process ◽  
Anodic Alumina ◽  
Wet Etching ◽  
Etching Time ◽  
X Ray Diffraction ◽  
Aao Template ◽  
Si Substrate ◽  
X Ray ◽  
Anodic Alumina Templates

Abstract: Thin anodic alumina (AAO) templates with uniform nanoscale pore diameters and interpore distances were fabricated by a two-step anodization technique on a Si-based (AAO/Ti/Si structure) under controllable anodizing conditions. The obtained thin AAO templates were approximately 60 nm in pore diameter and 1.2 µm in length with 110 nm interpore distances in area of 1 cm2. A bottom barrier layer of the anodic alumina (AAO) templates was removed by a wet etching using phosphoric acid (5 wt%) under control of etching time. As an application, Cu nanorods arrays embedded in anodic alumina (AAO) template were fabricated by electrodeposition. The morphologies and structure of the templates and the Cu nanorods produced were analyzed using Field-emission scanning electron microscope (FESEM), Energy dispersive x-ray spectroscopy (EDX) and X-ray diffraction (XRD).

Improvement for Extraction Efficiency of Vertical GaN-Based LED on Si Substrate by Photo-Enhanced Wet Etching

2009 ◽  
Vol 29 (1) ◽  
pp. 252-255 ◽  
Author(s):  
周印华 Zhou Yinhua ◽  
汤英文 Tang Yingwen ◽  
饶建平 Rao Jianping ◽  
江风益 Jiang Fengyi
Keyword(s):  
Extraction Efficiency ◽  
Wet Etching ◽  
Si Substrate

Low-Temperature, Low-Pressure and Ultrahigh-Rate Growth of Single-Crystalline 3C-SiC on Si Substrate by ULP-CVD Using Organosilane

2010 ◽  
Vol 645-648 ◽  
pp. 147-150 ◽  
Author(s):  
Eiji Saito ◽  
Sergey Filimonov ◽  
Maki Suemitsu
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Growth Temperature ◽  
High Rate ◽  
Si Substrate ◽  
Single Crystalline ◽  
Step Process ◽  
Si Substrates ◽  
Sic Film

Temperature dependence of the growth rate of 3C-SiC(001) films on Si(001) substrates during ultralow-pressure (ULP: ~10-1 Pa) CVD using monomethylsilane has been investigated in detail by using pyrometric interferometry. A novel behavior, i.e. a sharp division of the growth mode into two regimes depending on the growth temperature, has been found to exist. Based on this finding, we have developed a two-step process, which realizes a low-temperature (900 °C), high-rate growth of single-crystalline 3C-SiC film on Si substrates, whose rate of 3 m/h is extremely high for this ULP process.

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