Effect of Plasma Etching on Wicking Property of Polypropylene Fiber

Plasma etching technology is used to treat Polypropylene fiber with different fineness. The result shows that the plasma etching treatment is useful to improve the wicking property of polypropylene, although too much time of treatment may be converse to the wicking property. A surface roughness theory is applied to explain the reason why the plasma can improve the wicking property. In this experiment, fibers with different treating time under certain voltage(180 V) and pressure(0.1 mm Hg)are used as experimental sample.

Comprehensive Study of SF_6/O_2 Plasma Etching for Mc-Silicon Solar Cells

The mask-free SF6/O2 plasma etching technique is used to produce surface texturization of mc-silicon solar cells for efficient light trapping in this work. The SEM images and mc-silicon etching rate show the influence of plasma power, SF6/O2 flow ratios and etching time on textured surface. With the acidic-texturing samples as a reference, the reflection and IQE spectra are obtained under different experimental conditions. The IQE spectrum measurement shows an evident increase in the visible and infrared responses. By using the optimized plasma power, SF6/O2 flow ratios and etching time, the optimal etticiency of 15.7% on 50 × 50mm2 reactive ion etching textured mc-silicon silicon solar ceils is achieved, mostly due to the improvement in the short-circuit current density. The corresponding open-circuit voltage, short-circuit current density and fill factor are 611 m V, 33.6 mA/cm2, 76.5%, respectively. It is believed that such a low-cost and high-performance texturization process is promising for large-scale industrial silicon solar cell manufacturing.

Surface properties of Al-doped ZnO thin film before and after CF_4/Ar plasma etching

Al-doped ZnO(AZO) is considered as an alternative to transparent conductive oxide materials.Patterning and achieving a stable surface are important challenges in the development and optimization of dry etching processes, which must be overcome for the application of AZO in various devices. Therefore, in this study, the etch rate and surface properties of an AZO thin film after plasma etching using the adaptive coupled plasma system were investigated. The fastest etch rate was achieved with a CF_(4)/Ar ratio of 50:50 sccm. Regardless of the ratio of CF_(4) to Ar,the transmittance of the film in the visible region exceeded 80%. X-ray photoelectron spectroscopy analysis of the AZO thin film confirmed that metal-F bonding persists on the surface after plasma etching. It was also shown that F eliminates O vacancies. Consequently, the work function and bandgap energy increased as the ratio of CF-4 increased. This study not only provides information on the effect of plasma on AZO thin film, but identifies the cause of changes in the device characteristics during device fabrication.

Investigation of material removal characteristics of Si(100)wafer during linear field atmospheric-pressure plasma etching

Atmospheric-pressure(AP)plasma etching provides an alternative method for mechanical grinding to realize wafer thinning of Si wafer.It can avoid the damages and micro-cracks that would be introduced by mechanical stress during the grinding process.In this study,the material removal characteristics of Si(100)wafer processed by linear field AP plasma generated using carbon tetrafluoride(CF4)as the reactive source were analyzed.This linear field plasma etching tool has a typical removal profile and the depth removal rate that can reach up to 1.082μm/min.The effect ofO2 concentration on the removal ratewas discussed and the surfacemorphology during the process was characterized using scanning electron microscopy.It is shown that the subsurface damage layer was gradually removed during the etching process and the surface was observed to be smoothened with the increase of the etching depth.This present work contributes a basic understanding of the linear field AP plasma etching performance with different gas composition and the typical characteristics would be further applied to damage-free precision removal of Si.

Competitive effect between roughness and mask pattern on charging phenomena during plasma etching

In the plasma etching process,the edge roughness and mask pattern usually play a significant role in the deformation of holes under the influence of the charging effect.The competitive effect between these two factors has been investigated,focusing on the surface charging in a hexagonal array,with various values of roughness parameters(amplitude(A)and wavelength(W))and distances between holes(L).A series of classical particle dynamic simulations of surface charging,surface etching and profile evolution were used to investigate the effect of roughness and pattern on charging.This study showed that various roughness and patterns(represented by different values of L)can significantly influence surface distributions of the electric-field(Efield)and the etching rates on the mask surface.The simulations also showed that(1)the shape of the pattern array influences the mask hole profile during the etching process,i.e.a hexagonal array pattern tends to deform the profile of a circular mask hole into a hexagonal hole;(2)pattern roughness is aggravated during the etching process.These factors were found to be significant only at a small feature pitch and may be ignored at a large feature pitch.Possible mechanisms of these results during the etching process are discussed.This work sheds light on the ways to maintain pattern integrity and further improve the quality of the pattern transfer onto the substrate.

Charging Effect in Plasma Etching Mask of Hole Array

It has already been found that the round shape of holes can be changed into hexagonal shape during plasma etching processes.This work aims to understand the mechanism behind such a shape change using particle simulation method.The distribution of electric field produced by electrons was calculated for different heights from the mask surface.It is found that the field strength reaches its maximum around a hole edge and becomes the weakest between two holes. The field strength is weakened as moving away from the surface.The spatial distribution of this electric field shows obvious hexagonal shape around a hole edge at some distances from the surface. This charging distribution then affects the trajectories of ions that fall on a mask surface so that the round hole edge is etched to become a hexagonal hole edge.The changing of this hole shape will again alter the spatial distribution of electric field to enhance the charging effect dynamically.

Factors Affecting the Top Stripping of GaAs Microwire Array Fabricated by Inductively Coupled Plasma Etching

The effects of different masks and patterns on the top stripping of GaAs microwire arrays fabricated by inductively coupled plasma etching for 20min and 40min are investigated. The results show that the mask layer is the main affect of the top stripping of the GaAs microwires in 40min. Increasing the mask layers and reducing the photoresist layers can prevent top stripping and result in a suitable GaAs microwire array.

Etching characteristics and surface modification of InGaSnO thin films under Cl_(2)/Ar plasma

Indium gallium tin oxide(IGTO)thin films have the potential for high mobility and lowtemperature processing,which makes them suitable for applications such as display backplanes and high-voltage switching devices.However,very few studies have investigated the plasmaetching characteristics of IGTO and changes in its properties after etching.In this study,the etching characteristics of IGTO were investigated using Cl_(2)/Ar plasma,and changes in surface properties were analyzed.Results showed that the etch rate increased with an increase in the proportion of Cl_(2),with the highest etch rate observed at 69 nm min^(-1)in pure Cl_(2)plasma with a gas flow rate of 100 sccm.Furthermore,increased radio-frequency power caused a rise in the etch rate,while a process pressure of 15 m Torr was optimal.The primary etching mechanism for IGTO thin films under Cl_(2)plasma was a chemical reaction,and an increased work function indicated the occurrence of defects on the surface.In addition,the etching process reduced the surface roughness of Cl_(2)-containing plasma,whereas the etching process in pure Ar plasma increased surface roughness.This study contributes to a better understanding of the plasmaetching characteristics of IGTO and changes in its properties after etching,providing valuable insights for IGTO-based applications.

Alkali and Plasma-Treated Guadua angustifolia Bamboo Fibers:A Study on Reinforcement Potential for Polymeric Matrices

This study focuses on treating Guadua angustifolia bamboo fibers to enhance their properties for reinforcement applications in composite materials.Chemical(alkali)and physical(dry etching plasma)treatments were used separately to augment compatibility of Guadua angustifolia fibers with various composite matrices.The influence of these treatments on the fibers’performance,chemical composition,and surface morphology were analyzed.Statistical analysis indicated that alkali treatments reduced the tensile modulus of elasticity and strength of fibers by up to 40%and 20%,respectively,whereas plasma treatments maintain the fibers’mechanical performance.FTIR spectroscopy revealed significant alterations in chemical composition due to alkali treatments,while plasma-treated fibers showed minimal changes.Surface examination through Scanning Electron Microscopy(SEM)revealed post-treatment modifications in both cases;alkali treatments served as a cleanser,eliminating lignin and hemicellulose from the fiber surface,whereas plasma treatments also produce rough surfaces.These results validate the impact of the treatments on the fiber mechanical performance,which opens up possibilities for using Guadua angustifolia fibers as an alternative reinforcement in composite manufacturing.

A Multi-Scale Study on Silicon-Oxide Etching Processes in C_4F_8/Ar Plasmas

A multi-scale numerical method coupled with the reactor,sheath and trench model is constructed to simulate dry etching of SiO_2 in inductively coupled C_4F_8 plasmas.Firstly,ion and neutral particle densities in the reactor are decided using the CFD-ACE＋ commercial software.Then,the ion energy and angular distributions（IEDs and IADs） are obtained in the sheath model with the sheath boundary conditions provided with CFD-ACE＋.Finally,the trench profile evolution is simulated in the trench model.What we principally focus on is the effects of the discharge parameters on the etching results.It is found that the discharge parameters,including discharge pressure,radio-frequency（rf） power,gas mixture ratios,bias voltage and frequency,have synergistic effects on IEDs and IADs on the etched material surface,thus further affecting the trench profiles evolution.

Optimization of inductively coupled plasma etching for low nanometer scale air-hole arrays in two-dimensional GaAs-based photonic crystals

This paper mainly describes fabrication of two-dimensional GaAs-based photonic crystals with low nanometer scale air-hole arrays using an inductively coupled plasma （ICP） etching system. The sidewall profile and surface characteristics of the photonic crystals are systematically investigated as a function of process parameters including ICP power, RF power and pressure. Various ICP powers have no significant effect on the verticality of air-hole sidewall and surface smoothness. In contrast, RF power and chamber pressure play a remarkable role in improving sidewall verticality and surface characteristics of photonic crystals indicating different etching mechanisms for low nanometer scale photonic crystals. The desired photonic crystals have been achieved with hole diameters as low as 130 nm with smooth and vertical profiles by developing a suitable ICP processes. The influence of the ICP parameters on this device system are analyzed mainly by scanning electron microscopy. This fabrication approach is not limited to GaAs material, and may be efficiently applied to the development of most two-dimensional photonic crystal slabs.

Effect of Low-Frequency Power on Etching Characteristics of 6H-SiC in C4F8/Ar Dual-Frequency Capacitively Coupled Plasma

Dry etching of 6H silicon carbide （6H-SiC） wafers in a C4Fs/Ar dual-frequency capacitively coupled plasma （DF-CCP） was investigated. Atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS） were used to measure the SiC surface structure and compositions, respectively. Optical emission spectroscopy （OES） was used to measure the relative concentration of F radicals in the plasma. It was found that the roughness of the etched SiC surface and the etching rate are directly related to the power of low-frequency （LF） source. At lower LF power, a smaller surface roughness and a lower etching rate are obtained due to weak bombardment of low energy ions on the SiC wafers. At higher LF power the etching rate can be efficiently increased, but the surface roughness increases too. Compared with other plasma dry etching methods, the DF-CCP can effectively inhibit CχFγ films＇ deposition, and reduce surface residues.

Plasma-Etching Enhanced Mechanical Polishing for CVD Diamond Films

Chemically vapor deposited diamond films were etched at different parameters using oxygen plasma produced by a DC （direct current） glow discharge and then polished by a modified mechanical polishing device. Scanning electron microscope, atomic force microscope and Raman spectrometer were used to evaluate the surface states of diamond films before and after polishing. It was found that a moderate plasma etching would produce a lot of etch pits and amorphous carbon on the top surface of diamond film. As a result, the quality and the efficiency of mechanical polishing have been enhanced remarkably.

Plasma atomic layer etching of GaN/AlGaN materials and application: An overview

With the development of the third generation of semiconductor devices,it is essential to achieve precise etching of gallium nitride(GaN)materials that is close to the atomic level.Compared with the traditional wet etching and continuous plasma etching,plasma atomic layer etching(ALE)of GaN has the advantages of self-limiting etching,high selectivity to other materials,and smooth etched surface.In this paper the basic properties and applications of GaN are presented.It also presents the various etching methods of GaN.GaN plasma ALE systems are reviewed,and their similarities and differences are compared.In addition,the industrial application of GaN plasma ALE is outlined.

Enhancement of output power density in a modified polytetrafluoroethylene surface using a sequential O_(2)/Ar plasma etching for triboelectric nanogenerator applications

In this work,the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene(PTFE)triboelectric nanogenerator(TENG).Enhancing surface area by a powerful O_(2) and Ar bipolar pulse plasma etching without the use of CF_(4) gas has been demonstrated for the first time.TENG with modified surface PTFE using a sequential two-step O_(2)/Ar plasma has a superior power density of 9.9 W·m^(-2),which is almost thirty times higher than that of a pristine PTFE TENG.The synergistic combination of high surface area and charge trapping sites due to chemical bond defects achieved from the use of a sequential O_(2)/Ar plasma gives rise to the intensified triboelectric charge density and the enhancement of power output of PTFE-based TENG.The effects of plasma species and plasma etching sequence on surface morphologies and surface chemical species were investigated by a field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM),and X-ray photoelectron spectroscopy(XPS).The correlation of surface morphology,chemical structure,and TENG performance was elucidated.In addition,the applications of mechanical energy harvesting for lighting,charging capacitors,keyboard sensing and operating a portable calculator were demonstrated.

Transfer of Machined Patterns on an Aluminum Plate to Pyrex Glass Using Reactive Ion Etching SF_(6) Plasma without Masks

A method for etching the surface of a Pyrex glass substrate using the Reactive Ion Etching process without the use of masks is reported. Variations in the machined surface on an auxiliary plate, manufactured in aluminum and placed below a Pyrex glass slide, were transferred to the upper surface of the substrate. SF6 as etching gas and low pressure chamber to promote the increase of mean free path of ions were used. Two etching ratios were found, general, that affects the entire surface of the substrate, and differential, which generates the relief on the surface of the glass. Differential etching depth showed a linear behavior with respect to time;the mean differential etching rate obtained was 43 nm/min. The same phase between the auxiliary plate machining and the etched pattern on the substrate is preserved. With this technique it was possible to manufacture convex and concave surfaces;some examples are given. The arithmetic mean roughness achieved with the proposed method was found to be N1 class, ideal for the development of optical corrector plates.

High Selective Etching of Aluminum Alloys In High Plasma Density Reactor

An inductively coupled plasma (ICP) discharge and its etching behaviors for aluminum alloys were investigated in this report. A radio frequency power supply was used for plasma generation. The unique hardware configuration enabled one to control ion energy separately from plasma density. Plasma properties were measured with a Langmuir probe. Electron temperature, plasma potential and plasma density were found to be comparable with those reported from Electron Cyclotron Resonance (ECR) and other types of reactors[1].A mixture of HBr and chlorine gases were used for this aluminum etch study. Experimental matrices were designed with Response Surface Methodology (RSM) to analyze the process trends versus etch parameters, such as source power, bias power and gas composition. An etch rate of 8500A to 9000A per minute was obtained at 5 to 15 mTorr pressure ranges. Anisotropic profiles with high photoresist selectivity (5 to 1) and silicon dioxide selectivity greater than 10 were achieved with HBr addition into chlorine plasma.Bromine-containing chemistry for an aluminum etch in a low pressure ICP discharge showed great potential for use in ULSI fabrication. In addition, the hardware used was very simple and the chamber size was much smaller than other high density plasma sources.

Yttrium‐and nitrogen‐doped NiCo phosphide nanosheets for high‐efficiency water electrolysis

Engineering high‐performance and low‐cost bifunctional catalysts for H_(2)(hydrogen evolution reaction[HER])and O_(2)(oxygen evolution reaction[OER])evolution under industrial electrocatalytic conditions remains challenging.Here,for the first time,we use the stronger electronegativity of a rare‐Earth yttrium ion(Y^(3+))to induce in situ NiCo‐layered double‐hydroxide nanosheets from NiCo foam(NCF)treated by a dielectric barrier discharge plasma NCF(PNCF),and then obtain nitrogen‐doped YNiCo phosphide(N‐YNiCoP/PNCF)after the phosphating process using radiofrequency plasma in nitrogen.The obtained NYNiCoP/PNCF has a large specific surface area,rich heterointerfaces,and an optimized electronic structure,inducing high electrocatalytic activity in HER(331mV vs.2000mA cm^(−2))and OER(464mV vs.2000mA cm^(−2))reactions in 1MKOH electrolyte.X‐ray absorption spectroscopy and density functional theory quantum chemistry calculations reveal that the coordination number of CoNi decreased with the incorporation of Y atoms,which induce much shorter bonds of Ni and Co ions and promote long‐term stability of N‐YNiCoP in HER and OER under the simulated industrial conditions.Meanwhile,the CoN‐YP_(5)heterointerface formed by plasma N‐doping is the active center for overall water splitting.This work expands the applications of rare‐Earth elements in engineering bifunctional electrocatalysts and provides a new avenue for designing highperformance transition‐metal‐based catalysts in the renewable energy field.

The Implementation of the Surface Charging Effects in Three-Dimensional Simulations of SiO_(2) Etching Profile Evolution

Refined control of etched profile in microelectronic devices during plasma etching process is one of the most important tasks of front-end and back-end microelectronic devices manufacturing technologies. A comprehensive simulation of etching profile evolution requires knowledge of the etching rates at all the points of the profile surface during the etching process. Electrons do not contribute directly to the material removal, but they are the source, together with positive ions, of the profile charging that has many negative consequences on the final outcome of the process especially in the case of insulating material etching. The ability to simulate feature charging was added to the 3D level set profile evolution simulator described earlier. The ion and electron fluxes were computed along the feature using Monte Carlo method. The surface potential profiles and electric field for the entire feature were generated by solving Laplace equation using finite elements method. Calculations were performed in the case of simplified model of Ar+/CF4 non-equilibrium plasma etching of SiO2.

Angular Effects on F＋ Etching SiC： MD Study

Molecular dynamics （MD） simulations were performed to investigate F＋ continuously bombarding SiC surfaces with energies of 100 eV at different incident angles at 300 K. The simulated results show that the steady-state uptake of F atoms increases with increasing incident angle. With the steady-state etching established, a Si-C-F reactive layer is formed. It is found that the etching yield of Si is greater than that of C. In the F-containing reaction layer, the SiF species is dominant with incident angles less than 30°. For all incident angles, the CF species is dominant over CF2 and CF3.