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Spectroscopic studies of the first micro-photoluminescence (micro-PL) of GaInAsP single quantum wires made by dry etching and regrowth are presented.

Low-damage hard-mask (HM) plasma-etching technology for porous SiOCH film (k = 2.6) has been developed for robust 65-nm-node Cu dual damascene interconnects (DDIs). No damage is introduced by fluorocarbon plasma etching irrespective of whether rigid (k = 2.9) or porous (k = 2.6) SiOCH films are used, due to the protective CF-polymer layer deposited on the etched sidewall. The etching selectivity of the SiOCH films to the inorganic HMs is kept high by controlling the radical ratio of carbon relative to oxygen in the etching plasma gas. However, oxidation damage penetrates the films from the sidewalls due to the 02 plasma used for photoresist ashing. This damage is increased by the porous structure. As a result, we developed a via-first multi-hard-mask process for the DD structure in porous SiOCH film with no exposure to 02-ashing plasma, and we controlled the via-taper angle by RF bias during etching. We fabricated robust Cu DDIs with tapered vias in porous SiOCH film that can be applied to 65-nm-node ULSIs and beyond. Index Terms--Author, please supply your own keywords or send a blank e-mail to keywords@ieee.org to receive a list of suggested keywords.

The etching characteristics of atomic force microscopy (AFM) probe-grown ultrathin oxides (AFM oxides) are described. The probe revealed that AFM oxide growth is related to Si out-diffusion while the etching rate of ultrathin AFM oxides is dependent on the SiOH silanol reactive sites.

A very simple method for micropatterning flat plastic substrates that can be used to build microfluidic devices is demonstrated. Patterned poly(dimethylsiloxane) elastomer is used as a template to control the flow path of an etching solvent through a channel design to be reproduced on the plastic substrate. The etching solvent was a acetone/ethanol mixture for poly(methyl methacrylate) substrates or a dimethylformamide/acetone mixture for polystyrene. The method is extremely fast in that duplicate plastic substrates can be patterned in just a few minutes each. We identified conditions that lead to smooth channel surfaces and characterized the rate of etching under these conditions. We determined that, for sufficiently short etching times (shallow channel depths), the etch rate is independent of the linear flow rate. This is very important since it means that the etch depth is approximately constant even in complex channel geometries where there will be a wide range of etchant flow rates at different positions in the pattern to be reproduced. We also demonstrate that the method can be used to produce channels with different depths on the same substrate as well as channels that intersect to form a continuous fluid junction. The method provides a nice alternative to existing methods to rapidly fabricate microfluidic devices in rigid plastics without the need for specialized equipment.

The evolution of nanoscale pores or dimples during ion etching of GaN is used to measure the magnitude of the curvature-dependent roughening. The density of these dimples remained constant during the etch process but the dimples are observed to grow larger in size until coalescence occurred.

An investigation on the influence of the fluorocarbon gas (C5F8, C4F8, and CF4 molecules) flux onto SiO2 etching reaction is done in a beam apparatus. The findings suggest a significant contribution of direct SiO2 etching by fluorocarbon molecules in practical etching reactors, especially in case of the C5F8 molecules.

The deep ion implantation technology is presented to fabricate the gallium arsenide (GaAs) microstructures for microelectromechanical systems applications. The EL2 trap contributes to the formation of semi-insulating GaAs layers.

Gas flows in plasma etching reactors for semiconductor fabrication became a chief consideration in designing second-generation reactors with higher etching rates. An axisymmetrical model based on the direct simulation Monte Carlo method has been developed for analyzing rarefied gas flows in a vacuum chamber with the conditions of downstream pressure and gas flow rate. By using this simulator, rarefied gas flows with radicals and etch-products were calculated for microwave-plasma etching reactors. The results showed that the flow patterns in the plasma chamber strongly depend on the Knudsen number and the gas-supply structure. The ventilation of the etch-products in the plasma chamber was found to be improved both for higher Knudsen numbers and for gas-supply structures of the downward-flow type, as compared with those of the radial-flow or upward-flow types. [DOI: 10.1115/1.1459074]

The effects of surface treatment, inductively coupled plasma (ICP) etching and thermal annealing on surface and optical properties of p-type GaN were studied. This chemical treatment is effective in removing surface contaminants that can improve electrical properties of the material.

A model to calculate etching rates in SiO2 features in fluorocarbon plasmas is presented. Two parameters were found to be important such as the polymer surface coverage at the bottom of the etched feature and the effective sticking coefficients of the neutral species on the sidewalls of the etched feature.

The organic low k film was etched in the inductively coupled high-density plasmas employing N2/H2 and N2/NH3 gases. Ratio of H and N radical densities would be important for etching of organic low k film employing N-H plasmas.

This paper presents the fabrication of a microchemical chip for the detection of fluorescence species in microfluidics. The microfluidic network is wet-etched in a Borofloat 33 (Pyrex) glass wafer and sealed by means of a second wafer. Unlike other similar chemical systems, the detection system is realized with the help of microfabrication techniques and directly deposited on both sides of the microchemical chip. The detection system is composed of the combination of refractive microlens arrays and chromium aperture arrays. The microfluidic channels are 60 [micro]m wide and 25 [micro]m deep. The utilization of elliptical microlens arrays to reduce aberration effects and the integration of an intermediate (between the two bonded wafers) aluminum aperture array are also presented. The elliptical microlenses have a major axis of 400 [micro]m and a minor axis of 350 [micro]m. The circular microlens diameters range from 280 to 300 [micro]m. The apertures deposited on the outer chip surfaces are etched in a 3000-[Angstrom]-thick chromium layer, whereas the intermediate aperture layer is etched in a 1000-[Angstrom]-thick aluminum layer. The overall thickness of this microchemical system is less than 1.6 mm. The wet-etching process and new bonding procedures are discussed. Moreover, we present the successful detection of a 10-nM Cy5 solution with a signal-to-noise ratio (SNR) of 21 dB by means of this system. [644] Index Terms--Fluorescence detection, glass-to-glass bonding, [micro]TAS, refractive microlens, wet etching.

Research on atomic hydrogen etching is examined in detail. Both spectrometry and photoelectron spectroscopy have been used in this study.

Synchrotron-radiation x rays were used for room temperature wet etching of GaAs.

The characterization of silicon 111 (Si(111)) surface treated with 40% NH4F solution was done using x-ray photoelectron spectroscopy and static secondary ion mass spectrometry. As-treated Si(111) surface was predominately terminated with monohydrides and free of contamination. Two distinct mechanisms were observed. First, dihydride terminated step silicon atoms were dissolved much faster than defect-free monohydride terminated ones. Second, dihydrides in the corner of (110) zigzag enclosed characteristic triangular pits led to fast erosion of silicon atoms.

Refractive prismatic and off-axis micro-optical elements have been fabricated in gallium phosphide by mass-transport smoothing of multistep and binary preforms, respectively. A total optical efficiency of greater than 94% was measured for the prism, while diffraction-limited collimation and steering were demonstrated with the off-axis lens. A qualitative discussion of possible errors in binary preform etching and their effects on the surface figure is also included.

The impact of etch parameters of platinum etching using Cl2/CO plasma on the etching properties and the etch profiles was examined. It was demonstrated that Pt can be etched using the mixed gas plasma. The etch mechanism is separated into two temperature regions, below and above 210 degrees C. Etching characteristics depended on Cl2 concentration in each temperature region. Findings suggested that Pt thin films for 1-Gbit dynamic random access memory were successfully patterned by using Cl2/CO plasma with SiO2 films as an etch mask.

A novel double-deck-shaped gate technology for 0.1 micrometer heterojunction field-effect transistors (HJFET) based on dry-etching processes was described. The technology used a T-shaped SiO2-opening and gate-metal filling techniques which cuts into half the external gate fringing capacitance of conventional T-shaped gate HJFETs and allows the fabrication of voidless refractory gate-electrodes which ensure high uniformity. The fabricated HJFETs provided higher performance since the technology was based on an all-dry-etching process.

A study revealed that etching rates for both InGaAs and InAlAs can be significantly altered by the exposition of surface metal when monitor windows are employed to measure the drain current of InAlAs/InGaAs-heterojunction-based field effect transistors during wet-chemical gate recess. The surface of Ni enhanced the etching rate to a degree much higher than that in its absence. Findings suggested that the selection of surface metal that lies beneath the resist openings can be important if gate recess grooves with desired shapes are to be formed.

The properties of copper deposition on silicon from buffered hydrofluoric aci (BHF) solutions were analyzed by employing transmission electron microscopy (TEM), atomic force microscopy, total reflection x-ray fluorescence and inductively coupled plasma mass spectroscopy. From TEM cross-sectional images, the morphology of sample surfaces was examined. Further, the relation between the mechanism of copper deposition and the etching of the silicon in BHF was investigated. The results are discussed.

A study was conducted to analyze double peak phenomenon in superconducting tunnel junction x-ray detectors. Square junctions were fabricated by the dc-sputtering of aluminum surface by photolithographic patterning using reactive ion etching. Results indicated that the double peak correlated with the dynamics of quasiparticles resulting from x-ray absorption events. In addition, the double peak phenomenon was influenced by by bias voltage and magnetic history.

We combined functionalities of two diffractive optics with almost 100X lateral and vertical scale-length difference onto a single fused-silica surface. Fine-scale (2-[[micro]meter]-period) gratings for beam sampling were printed in photoresist by interference lithography and transferred to the substrate by a hydrofluoric acid etch. Subsequently, 115-[[micro]meter]-linewidth stairstep gratings for color separation at focus were proximity printed and wet etched in a two-mask process. Line shapes of the lamellar sampling grating are remarkably preserved following etching of the much deeper color separation grating structures with this nominally isotropic etch process. Model simulations of isotropic etching of topographical features show good agreement with the measured shape evolution of the sampling grating profiles, and the simulations reveal the sensitivity of the final feature shape to its initial aspect ratio. As a rule of thumb, lamellar grating profiles can be etched approximately [0.08A.sup.-2] times their modulation depth, where A is their initial aspect ratio (height/width), before they evolve into a cusplike shape and begin to lose height.

Research was conducted to examine the selective wet etching of GaAs on AlxGa1-xAs for AlGaAs/InGaAs/AlGaAs pseudomorphic high electron mobility transistor (PHEMT). Methods used were current-voltage, etched step measurement, atomic force microscopy and x-ray photoelectron spectroscopy. Results show that the PHEMT exhibits excellent and reliable performance, proving the applicability of the solution to gate recess process.

Research was conducted to examine the silicon etching that takes place during the chemical vapor deposition (CVD) diamond growth as a function of the methane content in the gas phase using scanning electron microscopy and atomic force microscopy. AFM experiments were performed in the tapping mode on a Nanoscope III microscope. Diamond was grown by the hot filament chemical vapor deposition method. Results indicate that the etching of silicon is generally detrimental as generating low-density silicon surface such as Si(100).

Research was conducted to examine the surface etching of a Novolak-type polymer on Si wafers employing dielectric barrier discharges in oxygen at high pressures and room temperature. The oxygen demand for mineralization of the film was compared with the particle flux of atomic oxygen to the sample surface. Results indicate that no defects were observed at large gap spacings of 20 mm at the pressure range of 50-700 mbar while at the 7-mm-gap spacing, the polymer surface exhibited some defects, the extent of which increased as pressure increased.

Binary optics are an important part of modern optics, but they have some inherent problems because of their binary nature. The optics cannot achieve maximum efficiency unless the rms surface error can be reduced. A technique for smoothing jagged surfaces by use of isotropic etching is presented. We show that etching smoothes the binary nature and improves the optical efficiency. Key words: Binary optic smoothing, isotropic etching, surface modification.

Chemically etched substrate steps were employed in the development of high temperature directly coupled direct current superconducting quantum interference devices (DC-SQUIDs). A KrF laser ablation technique was used in depositing YBCO thin films on the step-edged MgO substrate. The bottom and top of the chemically etched step exhibited sharper edges as compared to steps fabricated through ion milling.

Excimer-laser microetching of a variety of materials is applied to the fabrication of surface-relief optical microstructures of arbitrary morphology, with particular emphasis on computer-generated holographic structures. High-definition, high-radiation-intensity selective laser ablative etching in conjunction with step-and-repeat (period) replication or raster (pixel) scanning is used. To support such developments, the characteristic etching properties of a wide range of solid materials, from metals to semiconductors and polymers, are studied. Optical-interconnect and generic object holograms are produced by means of this alternative one-step holographic information-recording method. Key words: Computer-generated holograms, optical interconnects, micro-optics, excimer laser, materials processing.

Electron-cyclotron-resonance (ECR) and reactive ion etching (RIE) rates for GaN, AlN, InN and InGaN are measured utilizing the same reactor and plasma parameters in Cl2/Ar or CH4/H2/Ar plasmas. The etch rates of all four materials are substantially faster for ECR relative to RIE conditions in both chemistries, suggesting that a high ion density is a significant parameter in the etch. Apparently, the nitride etch rates are at least an order of magnitude higher in the ECR discharges.

The impact of etching on the surface resistance and surface morphology of sputtered and laser ablated thin films of YBa2Cu3O(7-delta) were investigated. Specifically, reflection high energy electron diffraction and atomic force microscopy methods were used together with microwave measurements to characterize the films prior to and after etching with citric acid, nitric acid, Br-methanol, EDTA, disodium EDTA and ion milling. The experiments revealed that ion milling resulted in the most severe degradation of surface crystallinity and highest rise in surface resistance.

Wafers that are to be submitted to anisotropic etching in aqueous KOH are conventionally passivated with a silicon dioxide or nitride layer in which backside windows are etched to define the microstructures. A different method to mask the backside of a silicon wafer for this purpose is presented. The method makes use of the phenomenon that silicon is not etched in KOH when biased above the passivation potential. The mask is defined by applying a set of bias voltages to the front of the wafer instead of patterning a deposited passivation layer at the backside, for which an accurate double-sided alignment is required. The feasibility of the method was demonstrated with the fabrication of membranes and suspended masses of various sizes.

High resolution transmission electron microscopy, Rutherford backscattering spectroscopy, secondary ion mass spectrometry and X-ray photoelectron spectroscopy of the surface properties of a silicon surface arising due to CHF3/C2F6 reactive ion etching reveal a fluorine- and carbon-composed silicon layer with 9 different chemical bonds. Specific bonds decompose at 400 and 200 degrees Celsius in the silicon, while the silicon substrate does not contain planar defects or point defect clusters. NF3 plasma treatment is the most effective surface silicon residue eliminating process.

Planar-electron-beam-induced-current (PEBIC) technique helps investigate the destruction caused by reactive ion etching in silicon. The etched regions exhibit a decrease in the EBIC signal. The difference in the EBIC signal emission between etched and unetched regions is inversely proportional to temperature. The etched surfaces indicate a decrease in total acceptor dopant impurity.

Bombardment of oxygen and organ plasma molecules in novolac-based photoresist, polyimide and polymethylmethacrylate influences the rate of reactive ion etching. The oxygen plasmas exhibit an enhanced rate of etch mechanism when compared to that of the argon plasma. The enhancement is chemically effected and carbon production in oxygen plasmas is large when compared to argon plasmas.

Inversion layer mobility on trench gate structures are determined by a methodology that incorporates the measurement of sidewall and bottom surface mobilities. Trenches that are formed by the sulphur hexafluoride/oxygen method on the regions of diffused base UMOSFETs are experimentally studied to determine the layer mobility. The study enables the development of designs for the trench gate UMOS devices.

Evolution of a surface eroding by reactive-ion etching is determined by a new algorithm. Hamilton-Jacobi equation and entropy condition for a given etch rate influence the motion of the eroding surface. The algorithm directly tracks trajectories of shocks and rarefaction waves. Hence the method may be a generalization of characteristics. The algorithm also calculates slope discontinuities accurately, without artificial diffusion.

The ion energy distributions and ion angular distributions of CF+, CF2+ and CF3+ were measured at the powered electrode of a capacitively coupled parallel-plate reactor running on CF4. The results showed that there was a slight increase in the angular width as the CF4 pressure became greater. The effect of elastic scattering and dissociative collisions in the sheath resulted in the formation of continua in the energy distributions.

The influence of ion angular distributions on microloading in oxygen reactive-ion etching of submicrometer polymer trenches was investigated. The results showed that when direct impingement of particles onto the bottom surface of a structure was the dominant ablation mechanism, the effect of lower local etch rates could be correlated with the angularly broadened flux of oxygen ions.

Research was conducted on HF- and NH4OH-treated (111)Si surfaces using spectroscopic ellipsometry. Results showed that removal of surface oxide was caused by aqueous HF etching. This effect forms Si surfaces ending with atomic hydrogen. Results also showed that protracted Si etching caused roughening of sample surfaces.

The surface reflectivity and etch rates of polyimide (Kapton H) after exposure to double-pulsed 308 nm laser radiation were investigated. The results showed that surface reflectivity underwent both transient and permanent changes when exposed to pulses above the ablation threshold. Incident probe radiation by particles in the plume dominated the process above threshold.

A new process for the highly selective etching of phosphorous-doped polycrystalline silicon is evaluated. Experiments are performed wherein a wafer sample is subjected to an externally applied magneticfield. Cl2 gas is introduced in the etching process at temperatures below zero degrees centigrade. The etched surfaces are then analyzed by x-ray photoelectron spectroscopy. Results show that the use of Cl2 magnetron plasma enhances the cracking reaction rate of the etched silicon materials.