bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of PTFE Nanoemulsion as a Low Dielectric Constant Material ILD
Authors: Sun S. C. , Chiang Y. C. , Rosenmayer C. T. , Teguh J. , Wu H. 
Published: April 2011

AbstractPolytetrafluoroethylene (PTFE) has been studied as a low dielectric constant material for ULSI. A novel nanoparticle dispersion of PTFE was developed that permits the spin-coat deposition of PTFE with a thickness range of 0.2 to 1.5 μm. These PTFE nanoemulsions are aqueous emulsions containing sub-50 nm size PTFE particles and surfactant that are thermodynamically stable, optically clear, and have low viscosity and surface tension. The films cast from this nanoemulsion are uniform in thickness with a standard deviation of < 2%. From FTIR spectra, significant amounts of C-F bonds (1153 cm−1 and 1211 cm−1) are detected in the films. The index of refraction from ellipsometry measurement is about 1.35 and the dielectric constant measured from high frequency C-V curves is about 1.85. The dielectric strength is about 170 V/ μm. TGA data indicates a weight loss rate of less than 0.25%/hr. at 425 °C. The moisture absorption is less than 0.01%. After sintering, the films are extremely resistant to chemical attack by sulfuric acid, buffered HF, and positive photoresist developer. The etch rate in an oxygen plasma at 30 W is around 200 nm/min. Stud pull tests indicate good adhesion to SiO2, Al, and Cu. Results of thermal, dielectric, chemical, and adhesion tests indicate that these PTFE films have potential for use as an integrated circuit dielectric material.
Optimization of Pecvd Sin Films Using A Statistically Designed Experiment
Authors: Brierley Steven K. , Kazior Thomas E. , Nguyen Lan 
Published: April 2011

AbstractA statistically designed experiment was run to optimize the deposition of PECVD SiN on GaAs substrates. Five deposition parameters were varied: RF power, temperature, pressure, plasma frequency, and ammonia/silane ratio. Four film properties were used to evaluate the quality of the nitride: the fraction of hydrogen bound to nitrogen atoms, the index of refraction (and its uniformity), thickness uniformity, and stress. From the screening phase of the experiment, it was determined that only the plasma frequency and ammonia/silane ratio influenced the quality of the nitride film. High frequency deposition was preferable to low frequency deposition since it resulted in lower film stress. The results of the optimization phase showed that SiN films with near‐zero stress, low N‐H bond density and good index of refraction could be obtained by deposition at a very low ammonia/silane ratio.
Effect of Oxygen Dose Variation on the Simox Microstructure
Authors: Datta R. , Krishnamoorthy V. , Allen L.P. , Chandonnet R. , Farley M. , Jones K. S. 
Published: April 2011

AbstractThe effect of oxygen dose variation on the SIMOX SOI structure has been investigated extensively in this work. Keeping other implantation parameters constant, the dose has been varied from 0.2x1018cm–2 to 1.4xl018cm–2. Our studies show that a critical dose exists for a particular implant energy, below which a continuous buried oxide layer does not form. Further, the SiO2 precipitates enhance the pinning of defects in the as-implanted state which subsequently grow into threading dislocations. A dose window exists, where the dislocation density is a minimum.The oxygen depth distribution in the as-implanted and annealed state has been studied using SIMS. HRXRD measurements have been performed to reveal the strain state as a function of dose variation. The defect microstructure has been investigated using PTEM, XTEM and Secco Etching. AFM studies show the quality of the Si surface and Si/BOX (Buried OXide) interface roughness. This work gives us a fundamental understanding of the evolution of the defect microstructure and strain from the as-implanted to the annealed state using independent implantation parameter control.
Growth of Transparent SiO2 Thin Film on Silicon at Room Temperatüre by Using I72nm Xe2* Excimer Lamp
Authors: Suzuki T. , Murahara M. 
Published: April 2011

AbstractSiO2 insulator was fabricated by using Xe2* excimer lamp at room temperature. In this method, a mixrine of NF3 and O2 gases was employed as a reaction gas. When the NF3 and O2 gases were exposed to the Xe2* excimer lamp light NF3 and O2 gases inside the chamber where Si substrate was placed, SiFn and NO2 were produced by photo‐chemical reaction. The SiFn accumulates on the Si substrate, and SiO2 is formed by oxidation reaction between SiFn and NO2. Subsequently SiFn adheres onto the formed SiO2 and again oxidizes by NO2. These processes occur spontaneously, and on SiO2 film is grown. Experimental conditions were NF3:O2 = 10:1, the total gas pressure 330 torr, photo‐chemical reaction time 5 minutes, and chain reaction time 5 minutes. The results of the film characterization were a SiO2 film thickness of about 1500Å, a refractive index of 1.38, specific resistance of 1.67*1010 Ω cm and relative dielectric constant of 6.96.
Preparation and Physical Properties of BI2TI2O7 Single Crystal Thin Film on SI (100) Substrate by Mocvd
Authors: Wang Hong , Shang S. X. , Su X. J. , Wang Z. , Wang M. 
Published: April 2011

AbstractInsulating thin films of Bi2Ti2O7 with (111) orientation have been prepared on silicon (100)–substrates at a temperature range of 480–550 °C by a MOCVD technique. The dielectric and C‐V properties were studied. The dielectric constant (ɛ) and loss tangent (tanδ) were found to be 180 and 0.01, respectively. The temperature and frequency dependence of dielectric constant were also measured. The Bi2Ti2O7 films are suitable to be used as a novel buffer layer and new insulating gate material in FET devices.
Sputtered Barium Titanate Films for Capacitor Applications
Authors: Hung Tsao Bang , Fries Carr Sandra , Weimer Joseph A. 
Published: April 2011

AbstractBaTiO3 films prepared by RF sputtering was studied for capacitor applications. Some films produced have a capacitance storage of 0.85 μF/cm2, a high resistivity of 1014 ω‐cm, and a low dissipation factor of 0.005. The dielectric constant of these BaTi03 films were approximately 10 to 30, which is superior to that of the typical polymer film capacitor and had little dependence on frequency. However the breakdown strength of BaTi03 was approximately 5MV/meter. The theoretical breakdown strength of BaTi03 is reported to be as high as 200MV/m. The processing parameters of BaTi03 films must be optimized to obtain the potential benefit of the BaTi03.
Chemical Vapor Deposition and Properties of Amorphous Aluminum Oxide Films
Authors: Gordon Roy G. , Kramer Keith , Liu Xinye 
Published: April 2011

AbstractFilms of amorphous aluminum oxide were deposited from vaporized alkylaluminum alkoxide compounds and oxygen. For example, a gaseous mixture of triethyldialuminum tri-sec-butoxide vapor and dry air deposits amorphous aluminum oxide films on substrates heated to temperatures around 400 °C. Transparent, smooth, adherent films of aluminum oxide were formed on silicon, glass and metal substrates. The new precursors display a number of advantages over previously used sources for aluminum oxide. They are non-pyrophoric, low-viscosity, low-cost liquids. High deposition rates, over 0.2 μm/min, were observed. The coatings have high purity, high electrical resistivity and high transparency to light. They are excellent barriers to diffusion of water and of ions, such as sodium. These films are useful in optical coatings, as wear-resistant hard coatings, and as diffusion barriers that protect flat panel displays, computer microcircuits, solar cells and metals from corrosion and degradation by impurities.
Doped Yttrium Iron Garnet (Yig) Thin Films For Integrated Magneto-Optical Applications
Authors: Stadler Bethanie J.H. , Li Yi-Qun , Cherif Mondher , Vaccaro Kenneth , Lorenzo Joseph P. 
Published: April 2011

AbstractA novel single-source MOCVD technique was used to deposit Ce:YIG ((Ce,Y)3Fe5O12) films which were investigated for integrated magneto-optical applications, such as waveguide isolators. These films were grown on gadolinium gallium garnet substrates in order to optimize the growth conditions before growth on semiconductor substrates was attempted. We were able to achieve very high ratios of Ce:Y (= 0.4) due to the nonequilibrium nature of MOCVD. Ce:YIG films on GGG substrates were epitaxial with excellent optical and magnetic properties, along with high Faraday rotations that were comparable to commercial Bi:YIG. Planar waveguiding was observed in Ce:YIG films on both GGG and MgO substrates. MgO also proved to be a successful buffer layer for protecting the semiconductor substrates during YIG deposition. The Ce:YIG films on MgO-buffered GaAs had very promising magnetic properties, but the MgO deposition on InP must be optimized before successful Ce:YIG films on InP can be achieved.
Raman and Ft‐Ir Study on Structure and Its Stability of Hydrogenated Amorphous Germanium‐Nitrogen Alloys
Authors: Xu Jun , Chen Kunji , Feng Duan , Miyazaki Seiichi , Hirose Masataka 
Published: April 2011

AbstractA series of hydrogenated amorphous germanium‐nitrogen (a‐GeN:H) alloys have been synthesized by plasma enhanced chemical vapor deposition. The structure and its thermal stability have been investigated by means of Raman Scattering and Fourier Transform Infrared techniques. It was found that the structure is changed from Ge‐Ge‐like to Ge‐N‐like when the nitrogen content x in a‐Ge1‐xNx:H is larger than 0.3. Some a‐GeN:H alloys were annealed for 30min at different temperature and it is shown that the film structural stability is significantly improved compared with pure a‐Ge:H film.
Investigation of Dipolar Relaxation Processes in a Side-Chain Nonlinear Optical Polymer
Authors: Cheng Z. -Y. , Katiyar R. S. , Bauer S. , Bauer-Gogonea S. 
Published: April 2011

AbstractAmorphous thin films of a typical side-chain nonlinear optical polymer were investigated by means of dielectric spectroscopy and thermally stimulated depolarization current (TSDC) within the temperature range -40°C to 230°C. Three distinct relaxation processes, labelled α, β and γ were observed. The α-relaxation, associated with the glass transition, is well described by the Vogel-Fulcher relation, while the sub glass transition β and γ-relaxation follow Arrhenius relations. The advantage of TSDC over dielectric spectroscopy is demonstrated for the investigation of the weak β-relaxation in the side-chain polymer. Furthermore, the β -relaxation is responsible for the initial, fast decay of the electro-optical response of the side-chain polymer at room temperature.
Minimization of Di Water Consumption In Wet Clean Rinse Tanks
Authors: Cook J. 
Published: April 2011

AbstractThe use of resistivity‐monitored dump‐rinse tanks in semiconductor wet processing allows the rinse process to be optimized, substantially reducing DI water consumption while minimizing the deleterious effects of water on bare silicon surfaces. Optimization experiments performed on the Metals wet clean hoods at ACT yielded optimum rinse cycles consisting of two or three dump cycles plus an overflow rinse to 10ΜΩ, with a calculated savings of about 40,000 gallons of DI water (about 40%) per year compared to previously accepted standards. Experiments indicate that the time required for rinsing is a competing function of the effectiveness of each dump cycle and the time required to physically perform the chosen number of dump cycles.
In‐Situ Monitoring of Hf Reprocessing in an Industrial Scale Recirculator Bath
Authors: Reddy A.J. , Norga G.J. , Park A.S. , Smith A.L. , Michel J. , Kimerling L.C. , Parekh B. , Shyu J.‐H. , Deane E. 
Published: April 2011

AbstractHigh chemical purity is essential for achieving satisfactory device yield in submicron CMOS processing. Reprocessing of liquid chemicals to maintain high purity can drastically reduce both environmental impact and cost of ownership (CoO) of wafer cleaning operations. We propose the use of a novel membrane Filter technology for control of contamination spikes and reduction of liquid chemical usage in pre‐gate HF cleaning. To ensure filter effectiveness, we have developed an in‐process sensor that monitors solution cleanliness by measuring the deposition rate of reducible ions on silicon. Metals are detected through their effect on the surface recombination of photoexcited carriers. This detection method allows quantification of copper and noble metal ions down to 108 atoms/cm2 levels. We have investigated the effect of chemical purity during HF cleaning on the gate oxide integrity (GOI) of 70–200 Å gate oxides. A significant increase in the low‐field breakdown is observed for HF‐last cleaning using chemicals containing more than 10 ppt Cu. We present the results of Cu spiking experiments to evaluate our ability to quantify contamination down to the stringent levels required for an industrial scale wet‐bench. We observe a linear correlation between metal deposition rate and Cu concentration in the 1–5 ppb range.
Perhalogenated Organic By-Products from Plasma Etching Processes and Their Effects on Human Health and Environmental Impact
Authors: Bauer S. , Wolff I. 
Published: April 2011

AbstractComplex analytical and toxicological studies of the waste products from aluminium plasma etching were performed over a four-year period. Many different organic compounds were identified and quantified in the waste gases, vacuum pump oils, and the solid debris collected from the air pipe systems. The identified compounds were exclusively perhalogenated hydrocarbons. Toxicological investigations showed clear genotoxic, embryotoxic, and teratogenic effects resulting from the waste products.The study left no doubt, that workers in semiconductor production processes are potentially in danger of coming in contact with small amounts of plasma by-products, either through accidents, maintenance procedures, or insufficient protection.
Spontaneous and Stimulated Intersubband Emission Under Optical Pumping
Authors: Boucaud P. , Sauvage S. , Gauthier-Lafaye O. , Moussa Z. , Julien F.-H. , Prazeres R. , Glotin F. , Ortega J.-M. , Planel R. , Leburton J. P. , Berger V. , Nagle J. 
Published: April 2011

ABSTRACTWe have investigated the mid-infrared spontaneous and stimulated emission between confined subbands in the conduction band of GaAs/AlGaAs quantum wells. The carriers which give rise to the intersubband emission are excited in the upper subbands using an intersubband optical pumping in coupled asymmetric quantum wells. The quantum wells are designed using phonon engineering in order to obtain population inversion between the second and first excited subband. This is obtained by adjusting the subband energy spacing between E2 and E1 close to the optical phonon energy which in turn allows an efficient relaxation. We have first observed intersubband spontaneous emission between E3 and E2 at 14 μm using an intersubband pumping with a CO2 laser in resonance with the E1-E3 transition. In a second set of experiments, the quantum wells are embedded in an infrared waveguide. We have measured the stimulated intersubband gain using a picosecond two-color free electron laser. The first color bleaches the E1-E3 transition and provides the population inversion. The intersubband stimulated gain is measured versus the waveguide length and photon energy. Stimulated gains ≈ 80 cm−1 are reported thus demonstrating that laser emission under optical pumping appears feasible in optimized structures. Finally, we show that intersubband emission can also be observed in quantum wells using an interband optical pumping.
Stark Shift and Field Induced Tunneling in Doped Quantum Wells with Arbitrary Potential Profiles
Authors: Panda S. , Panda B. K. , Fung S. , Beling C. D. 
Published: April 2011

ABSTRACTThe energies and resonance widths of single doped quantum wells consisting of Al-GaAs/GaAs with rectangular and annealing induced diffusion modified shapes are calculated under an uniform electric field using the stabilization method. The electronic structure is calculated without an electric field in the finite temperature density functional theory with exchange-correlation potential treated in the local density approximation. Our scheme for solving the Schrödinger and Poisson equations is based on the Fourier series method. The electric field is added to the self-consistent potential and energies are obtained as a function of the combined width of the well and barriers. This yields us the stabilization graph from which the energies and resonance widths at different field strengths are extracted using the Fermi Golden rule.
Normal Incidence Photoresponse as a Function of Well Width in P-Type GaAs/AlGaAs Multi-Quantum Wells
Authors: Brown G. J. , Capano M. A. , Hegde S. M. , Eyink K. , Szmulowicz F. 
Published: April 2011

ABSTRACTWe have performed an optimization study of the mid-infrared photoresponse of p-type GaAs/AlGaAs Quantum Well Infrared Photodetectors (QWIPs) designed for normal incidence detection. In these p-type quantum wells, normal incidence absorption is allowed (by the dipole selection rules for optical transitions) especially for transitions from the heavy-hole ground state to the second light-hole state. Previous theoretical modeling predicted that this transition will produce the strongest bound-to-continuum infrared absorption when the second light-hole state is located very near the top of the GaAs quantum well. For AlGaAs barrier layers with 30% aluminum, our modeling showed that a well width between 45Å and 50Å would optimize the normal incidence photoresponse of this p-type QWIP. In this work, photore^oonse spectra are reported for well widths ranging from 40Å to 65Å. A series of samples were tudied in which only the GaAs well width was varied in two monolayer increments, from 11 to 20 monolayers. Photoluminescence and X-ray diffraction measurements were used to verify the composition, well width, and structural quality of each sample. This study verified that the spectral range of the normal incidence photoresponse is narrower, as predicted by theory, for well widths in which the second light-hole state approaches the top of the valence band well.
High Performance HgCdTe-Detectors Grown by Molecular Beam Epitaxy
Authors: Rajavel R. D. , Jamba D. M. , Jensen J. E. , Wu O. K. , Cockrum C. A. , Wilson J. A. , Patten E. A. , Kosai K. , Rosbeck J. , Goetz P. , Venzor G. 
Published: April 2011

ABSTRACTMolecular beam epitaxy (MBE) offers benefits such as the capability for growth of compositionally-tailored heterostructures and in-situ doping of HgCdTe alloys. These capabilities were applied to the growth of long wave infrared unispectral focal plane arrays (FPA) with 480×4 elements. The detectivity (D*) map of the FPA demonstrated performance that was higher than the specification value, with no defective channels. Two-color detectors with the n-p-n architecture, for the simultaneous detection of two closely spaced bands in the midwave infrared spectrum were also grown by MBE. These devices exhibited sharp turn-off and turn-on in both bands. The quantum efficiency was greater than 70% and average R°A values exceeded 1×106 Ω-cm2 in both bands. These result demonstrate that high performance HgCdTe devices can be grown by MBE.
The Role of Atomic Hydrogen for Substrate Cleaning for Growth of CdTe Buffer Layers at Reduced Temperatures on Silicon, CdTe, and HgCdTe
Authors: Hirsch L. S. , Yu Zhonghai , Richards-Babb M. R. , Myers T. H. 
Published: April 2011

ABSTRACTAtomic hydrogen is shown to be efficacious for cleaning CdTe and HgCdTe substrates for subsequent CdTe growth by molecular beam epitaxy. While single crystal ZnTe and CdTe growth was obtained on Si substrates that underwent an ex-situ HF-based etch, only polycrystalline CdTe or ZnTe could be obtained on surfaces cleaned using an atomic hydrogen source. This result is possibly related to gas-phase transport of Te to the Si surface.
Off-Area Bonding of HgCdTe Photoconductive Infrared Detectors using Tri-Layer Photolithography and Wet/Dry Etching Techniques
Authors: Manthripragada Sridhar , Hu Kelley , Peters Frank , Burgess Andre , Babu Sachidananda , Shi Jack , Krebs Danny , Mott D. Brent , Shu Peter 
Published: April 2011

ABSTRACTOn-area wire bonding of HgCdTe photoconductive (PC) infrared detectors usually causes material damage underneath the bonding pads. Such damage may propagate into the active area, potentially degrading performance and posing long-term reliability problems. Some off-area bonding fabrication techniques can also induce some degree of semiconductor material damage. In this paper, we report a relatively straightforward off-area bonding scheme that solves these problems. The process uses multiple photolithography and chemical etching steps to create a continuous slope or staircase in the HgCdTe leading down to the epoxy surface. The staircase ensures smooth step coverage for the subsequent metalization. Tri-layer photolithography (resist /metal/resist) and reactive ion etching (RIE) is then used to remove the epoxy in the bonding pad area. Since all areas other than the pad region are protected by the metal film, no RIE radiation damage is induced to the active area. The contact metalization is achieved by using standard liftoff techniques. Our so called staircase off-area bonding fabrication technique can be used to fabricate highly reliable, high density, small-size, detector arrays.
Quantum Well Intermixing in Gain As/Gainasp and Gaas/Algaas Structures Using Pulsed Laser Irradiation
Authors: Bryce A. C. , De La Rue R. M. , Marsh J. H. , Ooi B. S. , Qiu B. , Button C.C. , Roberts J.S. 
Published: April 2011

ABSTRACTAn essentially impurity free, direct write and potentially high spatial resolution quantum well intermixing technique using pulsed laser irradiation is reported. This technique uses a Q-switched Nd:YAG laser emitting at 1.06 μm with a pulse length of ∼20 ns and repetition rate of 10 Hz. The typical energy densities used for both Gain As/Gain AsP and GaAs/AlGaAs structures were ∼ 5 mJ mm−2. Multiphoton interactions with carriers lead to phonon emission, the phonons interact with the lattice thus generating point defects which diffuse during a subsequent annealing stage in a rapid thermal annealer and cause intermixing. Photoluminescence measurements have demonstrated that the spatial resolution of the process is better than the resolution of the PL measurement (ie better than 25 μm) and the technique has been used to write directly a grating of period 1.25 μm into a GalnAs/GalnAsP quantum well structure. This was achieved using a grating of period 2.5 μm etched into the surface of the substrate; when illuminated by the Q-switched pulses this grating generated a volume hologram of point defects within the sample at half the etched period. A clear dip in the transmission spectrum of the waveguide which had been processed in this way was observed at 1.525 μm. Differential bandgap shifts of up to 40 meV have been observed in GaAs/AlGaAs double quantum well samples. 3 μm wide ridge waveguide lasers were fabricated from the intermixed and control samples. The threshold currents of the intermixed and the control lasers were comparable. The slope efficiency of the intermixed lasers showed insignificant changes when compared to the as-grown lasers.