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14 Jun 1993

Volume 62, Issue 24, pp. 3065-3209

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Interband near‐infrared second‐harmonic generation with very large ‖χ(2)(2ω)‖ in AlSb/GaSb‐InAsSb/AlSb asymmetric quantum wells

Sandro Scandolo, Alfonso Baldereschi, and Federico Capasso

Appl. Phys. Lett. 62, 3138 (1993); http://dx.doi.org/10.1063/1.109107 (3 pages) | Cited 8 times

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We propose a novel steplike quantum‐well structure for second‐harmonic generation with very large ‖χ(2)(2ω)‖ in the near infrared, based on interband doubly resonant transitions. The structure is engineered so as to maximize the second‐order susceptibility χ(2)(2ω), which requires, in particular, avoiding too much overlap between the heavy‐hole and the lowest electron envelope functions. We show that the choice of a steplike asymmetry and of GaSb‐InAsSb compounds, instead of the conventional AlGaAs, leads to an enhancement of the second‐order susceptibility by about 30 times with respect to bulk GaAs, at pump wavelengths of 1.5 μm.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
78.66.Fd III-V semiconductors
78.30.Fs III-V and II-VI semiconductors

High resolution Si position sensor

K. A. M. Scott, A. K. Sharma, C. M. Wilson, B. W. Mullins, S. F. Soares, and S. R. J. Brueck

Appl. Phys. Lett. 62, 3141 (1993); http://dx.doi.org/10.1063/1.109108 (3 pages) | Cited 1 time

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We report on a simple 80‐μm‐diam Ni‐Si‐Ni back‐to‐back Schottky photodiode with a demonstrated vibration‐limited optical‐position sensitivity of <4‐nm transverse to an incident laser beam. This is two orders of magnitude higher than the previous best resolution reported for a solid‐state noninterferometric position sensor. The response time of the unbiased device was measured to be 350 ps. The position sensitivity limit resulting from background electronic noise is as low as 0.25 pm/√Hz. The short circuit photocurrent response is linear across the detector gap and is insensitive to changes in wavelength and laser spot sizes within the gap. The bandwidth of the sensor was found to be 2 GHz. A simple model, based primarily on the symmetry of the device, provides a qualitative understanding of these results.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
72.40.+w Photoconduction and photovoltaic effects

Roughness of the silicon (001)/SiO2 interface

Mau‐Tsu Tang, K. W. Evans‐Lutterodt, G. S. Higashi, and T. Boone

Appl. Phys. Lett. 62, 3144 (1993); http://dx.doi.org/10.1063/1.109109 (3 pages) | Cited 27 times

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We use synchrotron x‐ray diffraction to characterize the roughness of the buried Si(001)/SiO2 interface, for three types of oxide, without modification of the interface. We show that the thermal oxide interface is 0.5±0.1 times as rough as the native oxide interface, suggesting that the oxide growth decreases the roughness slightly. We also measure the roughness of a chemically grown oxide interface.
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81.65.-b Surface treatments
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.

Relationship among mobility, recombination kinetics, and optimized solar cell performance

C. M. Fortmann and D. Fischer

Appl. Phys. Lett. 62, 3147 (1993); http://dx.doi.org/10.1063/1.109110 (3 pages) | Cited 5 times

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A link between the observed steady state mobility and the diffusive velocity, the speed at which carriers move to distances greater than a single hop distance (<100 Å), is found to be an important transport consideration for amorphous silicon‐based devices. The electron diffusive velocity is a function of material fabrication technique. The diffusive velocity affects device performance through the recombination kinetics as it is this velocity at which carriers move toward interfaces and recombination centers. These new considerations lead to the surprising result that in solar cells, a poor electron mobility can lessen recombination losses.
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84.60.Jt Photoelectric conversion
73.50.Pz Photoconduction and photovoltaic effects
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Dependence of electron accumulation in AlSb/InAs quantum well on thin surface materials of InAs and GaSb

A. Furukawa

Appl. Phys. Lett. 62, 3150 (1993); http://dx.doi.org/10.1063/1.109111 (3 pages) | Cited 4 times

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The role of thin surface material in electron accumulation of an AlSb/InAs quantum‐well system is reported. Electron density transferred from surface to well is much smaller when InAs was grown at the surface than when GaSb was grown at the surface. This result is explained by the difference of surface pinning positions between InAs and GaSb. The surface pinning position of InAs is obtained to be lower by 0.2 eV than that of GaSb.  
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73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.20.At Surface states, band structure, electron density of states

Temperature control during chemical vapor deposition of polycrystalline silicon with substrate heating by microwaves

R. Buchta, S.‐L. Zhang, D. Sigurd, and K. Lindgren

Appl. Phys. Lett. 62, 3153 (1993); http://dx.doi.org/10.1063/1.109112 (3 pages) | Cited 7 times

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Contactless and accurate measurement of the temperature is an important issue in rapid thermal processing. In this letter we report on the variation of the emissivity of the surface during chemical vapor deposition of polycrystalline silicon onto oxidized silicon wafers. The observed periodic change in the emissivity of the polycrystalline silicon/silicon dioxide/silicon structure is due to interference phenomena in the growing layer. In these experiments the silicon wafers were heated by direct absorption of microwaves in a single wafer reactor. It is shown that with this method of heating, the change of emissivity does not influence the actual temperature of the substrate.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Real‐time, in situ monitoring of surface reactions during plasma passivation of GaAs

Eray S. Aydil, Zhen Zhou, Konstantinos P. Giapis, Yves Chabal, Jeffrey A. Gregus, and Richard A. Gottscho

Appl. Phys. Lett. 62, 3156 (1993); http://dx.doi.org/10.1063/1.109113 (3 pages) | Cited 10 times

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Real‐time, in situ observations of surface chemistry during the remote plasma passivation of GaAs is reported herein. Using attenuated total reflection Fourier transform infrared spectroscopy, the relative concentrations of ‐As‐O, ‐As‐H, ‐H2O, and ‐CH2 bonds are measured as a function of exposure to the effluent from a microwave discharge through NH3, ND3, H2, and D2. The photoluminescence intensity (PL) from the GaAs substrate is monitored simultaneously and used qualitatively to estimate the extent of surface state reduction. It was found that, while the ‐CHx(x = 2,3) and ‐As‐O concentrations are reduced rapidly, the rates at which the ‐As‐H concentration and the PL intensity increase are relatively slow. The concentration of ‐H2O on the GaAs surface increases throughout the process as surface arsenic oxides and the silica reactor walls are reduced by atomic hydrogen. These observations suggest that removal of elemental As by reaction with H at the GaAs–oxide interface limits the passivation rate.
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81.65.-b Surface treatments
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
73.20.-r Electron states at surfaces and interfaces

Blue emission of porous silicon

M. K. Lee and K. R. Peng

Appl. Phys. Lett. 62, 3159 (1993); http://dx.doi.org/10.1063/1.109114 (2 pages) | Cited 42 times

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Thermally treated porous silicon shows blue photoluminescence (400–520 nm) excited by a He‐Cd laser (320 nm) at room temperature. Stable and uniform Schottky blue light emitting diodes have been fabricated from thermally treated porous silicon in this work. The emission of blue light may be explained by the wide optical energy band gap attributed to the quantum wire effect.
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78.55.Hx Other solid inorganic materials
85.60.Jb Light-emitting devices
78.60.Fi Electroluminescence
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Quenching of electron‐acoustic phonon scattering in quantum wires by a magnetic field

N. Telang and S. Bandyopadhyay

Appl. Phys. Lett. 62, 3161 (1993); http://dx.doi.org/10.1063/1.109115 (3 pages) | Cited 15 times

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We demonstrate the possibility of a dramatic quenching of acoustic phonon scattering in semiconductor quantum wires due to an external magnetic field. This quenching is important in understanding the suppression of inelastic backscattering at high magnetic fields which leads to the quantum Hall effect (in the Büttiker picture). Additionally, such quenching can give rise to strong negative magnetoresistance in narrow quantum wires which may have important applications in electronic devices and magnetic field sensors.
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72.20.Dp General theory, scattering mechanisms
72.20.My Galvanomagnetic and other magnetotransport effects
72.10.Di Scattering by phonons, magnons, and other nonlocalized excitations
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Effects of interdiffusion on the polarization dependent refractive index of a strained InGaAs/GaAs quantum well

Joseph Micallef, E. Herbert Li, and Bernard L. Weiss

Appl. Phys. Lett. 62, 3164 (1993); http://dx.doi.org/10.1063/1.109116 (3 pages) | Cited 4 times

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The polarization dependent refractive index of disordered, strained InGaAs/GaAs single quantum wells is calculated using the complex dielectric function, taking into consideration the contributions from the Γ, X, and L Brillouin zones. At longer wavelengths the refractive index decreases as the extent of disordering increases, resulting in a positive refractive index step when the lateral confining regions are more extensively disordered. The structure also exhibits birefringence in the quantum well band edge to barrier band‐edge wavelength range which decreases with interdiffusion. The refractive index is polarization independent outside this wavelength range. Interdiffusion extends this zero birefringence to shorter wavelengths.
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78.66.Fd III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Charge transfer from poly( p‐phenylene vinylene) into molecularly doped polymer

H. Antoniadis, B. R. Hsieh, M. A. Abkowitz, and M. Stolka

Appl. Phys. Lett. 62, 3167 (1993); http://dx.doi.org/10.1063/1.109117 (3 pages) | Cited 16 times

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We describe photoinduced charge transfer process in a bilayer device comprised of poly(p‐phenylene vinylene) (PPV) layer and a trap‐free molecularly doped polymer containing diaryldiamine (TPD) dispersed in polycarbonate (PC). The time resolved charge transfer from PPV to TPD:PC in the presence of an electric field is analyzed. The injection (transfer) efficiency of the photoinduced holes from PPV into TPD:PC is about 25% holes/photons at electric fields at 4×105 V/cm or higher. Minimal trapping of photocarriers at the interface region between the two polymer layers is associated with this transfer.
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73.40.-c Electronic transport in interface structures
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.50.Pz Photoconduction and photovoltaic effects
73.61.Ph Polymers; organic compounds

Reduction of interface‐trap density in metal‐oxide‐semiconductor devices by irradiation

Artur Balasiński and T. P. Ma

Appl. Phys. Lett. 62, 3170 (1993); http://dx.doi.org/10.1063/1.109118 (2 pages) | Cited 3 times

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Annealing of interface defects in metal‐oxide‐semiconductor (MOS) devices by x‐ray irradiation has been observed. The effect occurs in rad‐hard devices which had been previously damaged severely by high‐field Fowler–Nordheim electron injection, but has not been observed in standard MOS devices which are not radiation‐hardened. A mechanism based on the recombination‐enhanced‐defect‐reactions process is proposed to explain the results.  
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73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.80.Cb X-ray effects
73.20.Hb Impurity and defect levels; energy states of adsorbed species
85.30.Tv Field effect devices

Enhancement of diffusion length of pregettered multicrystalline silicon solar cells by hydrogen ion implantation at the end of the process

S. Sivoththaman, M. Rodot, J. C. Muller, B. Hartiti, M. Ghannam, H. E. Elgamel, J. Nijs, and D. Sarti

Appl. Phys. Lett. 62, 3172 (1993); http://dx.doi.org/10.1063/1.109119 (2 pages) | Cited 3 times

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2×2 cm2 n+pp+ multicrystalline silicon solar cells have been fabricated using thin wafers less than 200 μm thick. A large electron diffusion length has been achieved in these wafers after metallic impurity gettering using a heavy phosphorus diffusion prior to cell processing. Further improvements in the electron diffusion length (Ln) and in the short circuit current (Jsc) of these cells are brought out by hydrogen ion implantation carried out through the back surface of the finished cell. A 25% increase in Ln and a 5.5% increase in Jsc are obtained.
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84.60.Jt Photoelectric conversion
72.40.+w Photoconduction and photovoltaic effects
61.72.Yx Interaction between different crystal defects; gettering effect
61.72.uf Ge and Si

Realization of an in‐plane‐gate single‐electron transistor

H. Pothier, J. Weis, R. J. Haug, K. v. Klitzing, and K. Ploog

Appl. Phys. Lett. 62, 3174 (1993); http://dx.doi.org/10.1063/1.109120 (3 pages) | Cited 11 times

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By etching narrow trenches in an AlGaAs/GaAs heterostructure and defining a channel and six in‐plane gates in the two‐dimensional electron gas, a single‐electron transistor is produced in a simple way. As expected from charging effects, the conductivity of the transistor oscillates with the voltage on each gate. However, in contrast to metallic devices or heterostructure devices with metallic top gates, the voltage dependent depletion of the gates themselves leads to changes in the period of the oscillations.
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73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.40.Gk Tunneling
85.30.Tv Field effect devices

Electrical quenching of photoluminescence from porous silicon

Hideki Koyama, Tsuyoshi Oguro, and Nobuyoshi Koshida

Appl. Phys. Lett. 62, 3177 (1993); http://dx.doi.org/10.1063/1.109121 (3 pages) | Cited 23 times

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We have studied the visible photoluminescence (PL) of porous silicon (PS) under the condition that a bias voltage is applied in the direction of the PS layer thickness. It is shown, for the first time, that the PL intensity is sharply decreased when increasing the voltage. This electrical PL quenching was completely reversible. This phenomenon is interpreted as to arise from field‐enhanced tunneling of carriers between silicon crystallites. The result presented here strongly suggests that the visible luminescence of PS is not based on electronic transitions in some molecular substance, but on the radiative recombination in Si nanocrystallites.
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78.55.Hx Other solid inorganic materials
78.60.Fi Electroluminescence
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Novel shadow mask molecular beam epitaxial regrowth technique for selective doping

K. H. Gulden, X. Wu, J. S. Smith, P. Kiesel, A. Höfler, M. Kneissl, P. Riel, and G. H. Döhler

Appl. Phys. Lett. 62, 3180 (1993); http://dx.doi.org/10.1063/1.109122 (3 pages) | Cited 9 times

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We present a novel molecular beam epitaxial regrowth technique which provides a simple and convenient way for the in situ lateral structuring of the doping profiles and growth rates on a μm scale. We achieve excellent selective contacts to the respective doping layers for device dimensions varying from several 100 μm down to several μm. Keldysh based n‐i‐p‐i modulator structures, fabricated with our new method, exhibit an on/off ratio of 6:1 for a voltage swing of 7 V without enhancement by additional Bragg mirrors.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
42.79.Hp Optical processors, correlators, and modulators

Effects of ion beam defect engineering on carrier concentration profiles in 50 keV P+‐implanted Si(100)

Qing‐tai Zhao, Zhong‐lie Wang, Tian‐bing Xu, Pei‐ran Zhu, and Jun‐si Zhou

Appl. Phys. Lett. 62, 3183 (1993); http://dx.doi.org/10.1063/1.109123 (3 pages) | Cited 3 times

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Shallower carrier concentration profiles in 50 keV P+‐implanted Si(100) after annealing at 1000 °C for 1 h have been observed when a buried amorphous layer was formed by an additional irradiation of 1.0 MeV Si+ ions prior to annealing (i.e., ion beam defect engineering process). The secondary defects formed in the MeV Si+ damaged region act as gettering sites for the collection of interstitials from the shallower depths which are responsible for the transient diffusion of P, and therefore the transient diffusion of P is reduced and the carrier concentration profiles become shallower.
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61.72.uf Ge and Si
61.72.Yx Interaction between different crystal defects; gettering effect
61.80.Jh Ion radiation effects
61.72.Cc Kinetics of defect formation and annealing

High resolution x‐ray diffraction of periodic surface gratings

P. van der Sluis, J. J. M. Binsma, and T. van Dongen

Appl. Phys. Lett. 62, 3186 (1993); http://dx.doi.org/10.1063/1.109124 (3 pages) | Cited 18 times

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We show that very clear satellite peaks (up to the 22nd order) from periodic surface gratings in InP can be obtained in a rocking curve provided that the appropriate diffraction geometry is chosen. For (001) oriented Si, InP, or GaAs substrates with corrugations in the [110] direction, measured with CuKα1, the optimal geometry is best approximated by the 113 reflection measured with a high angle of incidence. Due to beam compression, caused by the asymmetry of the reflection, this reflection is also suited to obtain two‐dimensional reciprocal space maps. A simple slit can be used to obtain adequate detector resolution. The maps reveal in detail the shape of the grating. They are compared with model calculations based on Fourier transformation of the shape of the grating‐crystal assembly.
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61.05.cf X-ray scattering (including small-angle scattering)
61.05.cj X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc.
68.55.-a Thin film structure and morphology
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Selective etching of InP and InGaAsP over AlInAs using CH4/H2 reactive ion etching

H. E. G. Arnot, R. W. Glew, G. Schiavini, L. J. Rigby, and A. Piccirillo

Appl. Phys. Lett. 62, 3189 (1993); http://dx.doi.org/10.1063/1.109125 (3 pages) | Cited 9 times

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Selective etching of InP and InGaAsP over AlInAs was obtained using CH4/H2 reactive ion etching without the addition of a fluorine containing gas. By tuning the methane‐to‐hydrogen ratio, pressure, and power, sputter desorption of the reacted AlInAs etch products can be inhibited, thus enabling AlInAs to be used as an etch stop layer. The use of a fluorine free mixture enables dielectrics such as silicon dioxide or nitride to be used as the masking material.  
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81.65.-b Surface treatments
85.40.Hp Lithography, masks and pattern transfer
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Chemically induced shifts in the photoluminescence spectra of porous silicon

K.‐H. Li, C. Tsai, J. Sarathy, and J. C. Campbell

Appl. Phys. Lett. 62, 3192 (1993); http://dx.doi.org/10.1063/1.109126 (3 pages) | Cited 32 times

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The observation of photoluminescence (PL) spectral shifts during anodization of porous Si and after immersion in different chemical solutions is reported. These shifts in the PL spectra are attributed to changes in the surface chemistry achieved by changing the composition of the electrolyte in which the samples are immersed. Using this approach the emission has been repeatedly cycled (≳100 times) between green and red.
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78.55.Hx Other solid inorganic materials
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
82.45.-h Electrochemistry and electrophoresis

Linewidth measurements of Josephson flux‐flow oscillators in the band 280–330 GHz

Y. M. Zhang, D. Winkler, and T. Claeson

Appl. Phys. Lett. 62, 3195 (1993); http://dx.doi.org/10.1063/1.109127 (3 pages) | Cited 36 times

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An integrated receiver consisting of two Josephson flux‐flow oscillators and a superconductor‐insulator‐superconductor (SIS) mixer has been used to measure the linewidth of the oscillators. The oscillators are coupled to the SIS mixer using two centerfed interdigital capacitors, one of which with a fairly weak (−20 dB) coupling. By biasing the two oscillators (a few microvolt apart) on their velocity matching steps, the two resulting oscillations (280–330 GHz) were mixed in the SIS mixer. The difference frequency was amplified and detected on a spectrum analyzer. The combined linewidth of the two oscillators was 2.1 MHz throughout the band. The calculated available power incident on the SIS mixer was 430 nW at 320 GHz. The rf power from the oscillators, which could be tuned by changing the current bias, is high enough to pump the SIS mixer optimally.
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85.25.Dq Superconducting quantum interference devices (SQUIDs)
84.30.Qi Modulators and demodulators; discriminators, comparators, mixers, limiters, and compressors
74.50.+r Tunneling phenomena; Josephson effects

Electric field effect control of a superconducting YBa2Cu3O7 inductor

Y. Gim, C. Doughty, X. X. Xi, A. Amar, T. Venkatesan, and F. C. Wellstood

Appl. Phys. Lett. 62, 3198 (1993); http://dx.doi.org/10.1063/1.109103 (3 pages) | Cited 8 times

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We discuss the design, fabrication, and testing of a thin‐film superconducting voltage‐controlled inductor which is made from a YBa2Cu3O7 (YBCO) superconducting field effect transistor. Applying voltage to an Au gate layer alters the areal carrier density, and hence the kinetic inductance, of an underlying 100‐nm‐thick YBCO channel layer. The channel is connected in series with an input coil to form a closed superconducting loop. We use a dc superconducting quantum interference device at 4.2 K to measure changes in loop inductance and find a fractional change in the kinetic inductance of about +2.6×10−4/V of applied gate voltage, close to the expected value.
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85.25.Qc Superconducting surface acoustic wave devices and other superconducting devices
74.25.F- Transport properties
84.32.Hh Inductors and coils; wiring
74.78.-w Superconducting films and low-dimensional structures

Precipitates in YBa2Cu3O7−δ thin films annealed at low oxygen partial pressure

S. Y. Hou, Julia M. Phillips, D. J. Werder, T. H. Tiefel, R. M. Fleming, J. H. Marshall, and M. P. Siegal

Appl. Phys. Lett. 62, 3201 (1993); http://dx.doi.org/10.1063/1.109624 (3 pages) | Cited 6 times

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We have studied the precipitates in YBa2Cu3O7−δ(YBCO) thin films grown by the BaF2 process in pO2=4 Torr and 700 °C. While stoichiometric films result in BaCuO2 surface precipitates, we have found Y2Cu2O5 precipitates embedded in the matrix of the same film. Off stoichiometric films with Ba/Y<1.5 have a precipitate‐free surface but with higher abundance of Y2Cu2O5 in the film matrix. The estimated densities of the two precipitates favor a stoichiometric YBCO film matrix. This behavior is not explainable in terms of phase equilibria and is attributed to kinetic effects. The electrical properties of the films degrade as the Ba/Y ratio deviates from 2.00.
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68.55.Nq Composition and phase identification
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors

Preparation of CaTiO3 heteroepitaxial thin films by excimer laser deposition

Tatsuhiko Fujii, Akira Fujishima, Takashi Hirano, and Takeshi Kobayashi

Appl. Phys. Lett. 62, 3204 (1993); http://dx.doi.org/10.1063/1.109078 (3 pages) | Cited 5 times

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CaTiO3 thin films were prepared by a 193 nm ArF excimer laser deposition method. Epitaxial CaTiO3 thin films were obtained on SrTiO3 (100) substrate and YBa2Cu3Oy (001) deposited on MgO (100) single‐crystal substrate. The grown CaTiO3 thin films orientated to (010) direction and the unit cell of CaTiO3 rotated 45° around the [100] axis of the SrTiO3 substrate. It also happened in CaTiO3/YBa2Cu3Oy/MgO system. The static dielectric constant was 120 at room temperature and reached 175 at lower temperatures.
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81.15.Fg Pulsed laser ablation deposition
68.55.-a Thin film structure and morphology
77.55.-g Dielectric thin films

Self‐consistent fluid modeling of radio frequency discharges in two dimensions

M. Dalvie, M. Surendra, and G. S. Selwyn

Appl. Phys. Lett. 62, 3207 (1993); http://dx.doi.org/10.1063/1.109079 (3 pages) | Cited 22 times

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Results from a two‐dimensional (2D) fluid simulation of a parallel plate, capacitively coupled radio frequency discharge bounded by a cylindrical insulator with a grounded exterior surface are presented. We find that the radial sheath at the insulator focuses current into the plasma region adjacent to the sheath. This 2D effect has important ramifications for the ionization rate, which peaks sharply in the metal‐insulator corners. We have experimentally observed the enhancement of the emission rate in a corner using spatially resolved optical emission spectroscopy. A ‘‘thick’’ insulator yields radial profiles for the time‐averaged plasma density and potential that are essentially uniform. A ‘‘thin’’ insulator, however, results in an off‐axis maximum in the plasma density and potential due to the corner ionization.
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52.80.Pi High-frequency and RF discharges
52.65.-y Plasma simulation
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