scholarly journals A New Dry Etching Method with the High Etching Rate for Patterning Cross–Linked SU–8 Thick Films

2016 ◽  
Vol 67 (3) ◽  
pp. 212-216 ◽  
Author(s):  
Jingning Han ◽  
Zhifu Yin ◽  
Helin Zou ◽  
Wenqiang Wang ◽  
Jianbo Feng
Keyword(s):  
Etching Rate ◽  
Chamber Pressure ◽  
Gas Mixture ◽  
Substrate Holder ◽  
Rf Power ◽  
Gas Concentration ◽  
High Etching Rate ◽  
Mems Device ◽  
The Cross ◽  
Difficult Issue

Abstract Photo sensitive polymer SU-8, owing to its excellent mechanical properties and dielectric properties on polymerization, is widely used in MEMS device fabrications. However, the removing, stripping or re-patterning of the cross-linked SU-8 is a difficult issue. In this paper, CF4/O2 gas mixture provided by a plasma asher equipment was used for the patterning of cross-linked SU-8 material. The RF power, the temperature of the substrate holder, chamber pressure and gas concentration were optimized for the cross-linked SU-8 etching process. When the CF4/O2 mixture contains about 5%CF4 by volume, the etching rate can be reached at 5.2 μm/min.

Realization of silicon nanopillar arrays with controllable sidewall profiles by holography lithography and a novel single-step deep reactive ion etching

2010 ◽  
Vol 1258 ◽  
Author(s):  
Yung-Jr Hung ◽  
San-Liang Lee ◽  
Brian J. Thibeault ◽  
Larry A. Coldren
Keyword(s):  
Etching Rate ◽  
Reactive Ion Etching ◽  
Single Step ◽  
Gas Mixture ◽  
Optical Performance ◽  
Ion Etching ◽  
Deep Reactive Ion Etching ◽  
High Etching Rate ◽  
Sidewall Angle ◽  
Nanopillar Arrays

AbstractA simple and efficient approach for fabricating silicon nanopillar arrays with a high aspect ratio and controllable sidewall profiles has been developed by using holographic lithography and a novel single-step deep reactive ion etching. During the etching process, scalloping of the sidewalls can be avoided while reserving the high mask selectivity and high etching rate. Besides, the sidewall angle of resultant patterns can be adjusted by tuning the composition of the gas mixture of single-step DRIE process. We further fabricate a tapered silicon nanopillar array and observe its photonic bandgap property. We believe that the good optical performance of this tapered silicon nanopillar array realized by the proposed approach shows the promising of this process for various applications.

Isotropic Etching of SiC

2008 ◽  
Vol 600-603 ◽  
pp. 651-654 ◽  
Author(s):  
Thomas Stauden ◽  
Florentina Niebelschütz ◽  
Katja Tonisch ◽  
Volker Cimalla ◽  
Gernot Ecke ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Substrate Temperature ◽  
Plasma Etching ◽  
Parallel Plate ◽  
Etching Rate ◽  
Chamber Pressure ◽  
Rf Power ◽  
Isotropic Etching ◽  
Parallel Plate Reactor ◽  
Substrate Temperatures

Isotropic etching of silicon carbide was achieved using a capacitive coupled parallel plate reactor in plasma etching mode and SF6 at elevated substrate temperatures. It was observed to be remarkable at substrate temperatures above 350°C. The influence of chamber pressure, masking materials, rf-power and substrate temperature were analyzed. Thereby, 8.5° off-axis oriented 4HSiC wafers exhibit a larger vertical and lateral etching rate compared to on-axis oriented SiC wafers. Additionally, the erosion of nitrogen containing masking material results in a reduction of the etching rates.

Top-gate ZnO-based TFTs by RF Sputtering

2007 ◽  
Vol 1035 ◽  
Author(s):  
Shahrukh Khan ◽  
Abbas jamshidi-Roudbari ◽  
Miltiadis Hatalis
Keyword(s):  
Thin Films ◽  
Power Density ◽  
Rf Sputtering ◽  
Visible Spectrum ◽  
Drain Current ◽  
Channel Length ◽  
Zno Thin Films ◽  
Chamber Pressure ◽  
Rf Power ◽  
Bridge Structures

AbstractThis work emphasizes room temperature deposition and fabrication of top-gated staggered structure ZnO-TFTs and integration of ZnO-TFT based simple logic circuits. We synthesized ZnO thin films by RF sputtering in an Ar/Oxygen ambience with no intentional heating of the substrates. The electrical, optical and structural properties of the ZnO thin films can be well-controlled by altering process parameters such as RF power density and relative Oxygen partial pressure. Typical deposition was carried out at a chamber pressure of 15 mTorr, Ar/Oxygen flow rates of 15 sccm/1 sccm and RF power density of 3W/cm2. The resistivity of the as-deposited films was between 104-106 Ù-cm with high optical transparency (>80%) in the visible spectrum and minimal surface roughness as detected by high-resolution AFM imaging. Gated van der Pauw and Kelvin-bridge structures were lithographically patterned to asses ZnO channel resistance. In the completed devices, a dual-stack (Ta2O5/SiO2) dielectric layer was effective in suppressing gate-leakage current below 10 pA and enabled depletion-mode ZnO-TFT operation exhibiting hard saturation. A Ti/Au metallization scheme was adopted to provide good ohmic contact to ZnO. TFTs retained well-behaved transfer characteristics down to a channel length of 4 ìm with on/off drain current ratio exceeding 105, threshold voltage between -15 V to -5 V and inverse sub-threshold slope of around 1.75 V/decade.

The Selectivity of Reactive Ion Etch of Ga0.5LIn0.49P/Gaas

1994 ◽  
Vol 337 ◽  
Author(s):  
J.W. Wu ◽  
S.H. Chan ◽  
K.C. Lin ◽  
C.Y. Chang ◽  
E.Y. Chang
Keyword(s):  
Etch Rate ◽  
Etching Rate ◽  
Bipolar Transistor ◽  
Heterojunction Bipolar Transistor ◽  
Gas Mixture ◽  
Precise Control

ABSTRACTThe Ga0.51In0.49p/GaAs system has better desired property (ΔEC >ΔEV) than the conventional AlGaAs/GaAs system for heterojunction bipolar transistor (HBT) application. However, in the fabrication of HBTs, a precise control of the etch of the epilayer is very important. In this study, CH4/H2 and BCl3/SF6 were used for the reactive ion etch of the Ga0.51In0.49P/GaAs. It is found that the etch rate of Ga0.51In0.49P could be higher than that of GaAs with CH4/H2 gas mixture under appropriate etching conditions. While in the case of BCl3/SF6, the etching rate of GaAs could be much higher than that of the Ga0.51In0.49P. By properly using CH4/H2 and BCl3/SF6, the fabrication of Ga0.51In0.49P-based device using reactive ion etch could be easily achieved.

scholarly journals Determination Of Gas Mixture Components Using Fluctuation Enhanced Sensing And The LS-SVM Regression Algorithm

2015 ◽  
Vol 22 (3) ◽  
pp. 341-350 ◽  
Author(s):  
Łukasz Lentka ◽  
Janusz M. Smulko ◽  
Radu Ionescu ◽  
Claes G. Granqvist ◽  
Laszlo B. Kish
Keyword(s):  
Support Vector Machine ◽  
Least Squares ◽  
Temperature Change ◽  
Nonlinear Regression ◽  
Ultraviolet Irradiation ◽  
Support Vector ◽  
Gas Mixture ◽  
Gas Concentration ◽  
Single Sensor

Abstract This paper analyses the effectiveness of determining gas concentrations by using a prototype WO3 resistive gas sensor together with fluctuation enhanced sensing. We have earlier demonstrated that this method can determine the composition of a gas mixture by using only a single sensor. In the present study, we apply Least-Squares Support-Vector-Machine-based (LS-SVM-based) nonlinear regression to determine the gas concentration of each constituent in a mixture. We confirmed that the accuracy of the estimated gas concentration could be significantly improved by applying temperature change and ultraviolet irradiation of the WO3 layer. Fluctuation-enhanced sensing allowed us to predict the concentration of both component gases.

Make Carbon nanotube-polymer composite thin: application to water quality

2011 ◽  
Vol 1346 ◽  
Author(s):  
C. Villeneuve ◽  
S. Pacchini ◽  
M. Dilhan ◽  
D. Colin ◽  
A. Brouzes ◽  
...  
Keyword(s):  
Composite Film ◽  
Plasma Treatment ◽  
Inner Core ◽  
Etching Rate ◽  
Water Molecules ◽  
Technology Process ◽  
Aligned Carbon Nanotubes ◽  
Internal Radius ◽  
High Etching Rate ◽  
Membrane Roughness

ABSTRACTThis paper reviews our works about the development of thin composite film based on aligned carbon nanotubes (CNT) forest, embedded in epoxy or PMMA polymer matrix, in order to fabricate membranes dedicated to water purification issue. Indeed, the small internal radius of nanotubes, the smoothness of their inner core and the hydrophobic properties of its interna surface induce remarkable flowing properties for water molecules. In this article, thinnin technology process is investigated to obtain composite film with opened CNT. Different etching techniques as grinding, Chemical Mechanical Polishing (CMP) and isotropic plasma O2ar investigated in term of etching rate and membrane roughness, using AFM and SEM characterizations. Results show CMP process in lapping configuration permits to obtain agreement between high etching rate and membrane roughness. Moreover, to improve water flowing through membrane, O2plasma treatment is used to remove polymer residue spread over CNT. Joint use of lapping and plasma treatment permits to obtain 35μm-thick nanoporous membrane with well-opened protruding nanotubes.

Low Energy Focused Ion Beam Processing

1992 ◽  
Vol 279 ◽  
Author(s):  
Kenji Gamo
Keyword(s):  
Focused Ion Beam ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Etching Rate ◽  
High Mobility ◽  
Low Energy ◽  
High Electron ◽  
Optimization Of Process Parameters ◽  
High Etching Rate

ABSTRACTFocused ion beam (FIB) techniques have many advantages which stem from being maskless and have attracted much interest for various applications includingin situprocessing. However, reduction of damage and improvement of throughput are problems awaiting solution. For reduction of damage, low energy FIB is promising and for improvement of throughput, understanding of the basic processes and optimization of process parameters based on this understanding is crucial. This paper discusses characteristics of low energy FIB system, ion beam assisted etching and ion implantation, and effect of damage with putting emphasize onin situfabrication. Low energy (0.05–25keV) FIB system being developed forms -lOOnm diameter ion beams and is connected with molecular beam epitaxy system. Many results indicate that low damage, maskless ion beam assisted etching is feasible using low energy beams. Recently it was also shown that for ion beam assisted etching of GaAs, pulse irradiation yields very high etching rate of 500/ion. This indicates that the optimization of the relative ratio of ion irradiation and reactant gas supply as important to achieve high etching rate. Low energy FIB is also important for selective doping for high electron mobility heterostructures of GaAs/GaAlAs, because high mobility is significantly degraded by a slight damage.

scholarly journals FEATURES OF PLASMA CHEMICAL ETCHING OF LITHIUM TANTALATE SUBSTRATE (LiTaO3)

2021 ◽  
pp. 188-190
Author(s):  
O.A. Fedorovich ◽  
O.V. Hladkovska ◽  
V.V. Hladkovskyi ◽  
A.F. Nedybaliuk
Keyword(s):  
Chemical Etching ◽  
Closed Loop ◽  
Etching Rate ◽  
Chemical Reactor ◽  
Optical Systems ◽  
Gas Mixture ◽  
Plasma Chemical ◽  
Plasma Chemical Reactor ◽  
Plasma Chemical Etching ◽  
Core Thickness

The results of researches of plasma chemical treatment of lithium monocrystalline tantalate (LiTaO3) from gas type, bias voltage (energy of chemically active ions) and from current of additional bias generator are given. A closed-loop electron drift plasma chemical reactor and gas mixtures containing Ar, Ar + ClС4, and Ar + SF6 were used for the experiments. It was found that the etching rate of LiTaO3 for the discharge in the gas mixture Ar + CCl4 is 14 times higher than all other mixtures that were used. It is shown that the proposed idea and approaches of LiTaO3 processing can be effectively applied for the production of optical systems with a minimum core thickness of about 2…3 μm.

Unexpectedly High Etching Rate of Highly Doped n-Type Crystalline Silicon in Hydrofluoric Acid

2013 ◽  
Vol 2 (9) ◽  
pp. P380-P383 ◽  
Author(s):  
L. Liu ◽  
F. Lin ◽  
M. Heinrich ◽  
A. G. Aberle ◽  
B. Hoex
Keyword(s):  
Hydrofluoric Acid ◽  
Crystalline Silicon ◽  
Etching Rate ◽  
High Etching Rate

scholarly journals 4H-Silicon Carbide Wafer Surface after Chlorine Trifluoride Gas Etching

2018 ◽  
Vol 924 ◽  
pp. 369-372 ◽  
Author(s):  
Shogo Okuyama ◽  
Keisuke Kurashima ◽  
Ken Nakagomi ◽  
Hitoshi Habuka ◽  
Yoshinao Takahashi ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Etching Rate ◽  
Concentric Circle ◽  
Wafer Surface ◽  
Deep Etching ◽  
Gas Distributor ◽  
High Etching Rate ◽  
Hole Arrays ◽  
Rate Profile ◽  
Gas Supply

In order to develop the high etching rate reactor for silicon carbide, the 50-mm-diameter C-face 4H-silicon carbide wafer was etched using the chlorine trifluoride gas at 500 °C. By the deep etching, the concentric-circle-shaped valleys were formed at the positions corresponding to the radii of the pin-hole arrays of the gas distributor, as predicted by the calculation. The etching rate profile of 4H-silicon carbide was concluded to have a relationship with the local chlorine trifluoride gas supply . The wafer bow was small, even the wafer was very thin, about 160 μm thick.

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