摘要:

We report type I phase‐matched blue second‐harmonic generation from periodically segmented channel ion‐exchanged waveguides in KTiOPO4with output wavelengths from 0.38 to 0.48 &mgr;m and efficiencies exceeding 50%/W cm2. Evidence is presented suggesting that these efficiencies result from ferroelectric domain reversals induced by waveguide fabrication. Waveguide structure, wavelength, and output power characteristics are presented.

ISSN:0003-6951    

DOI:10.1063/1.103945

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Spatial profiles of size and number density of aluminum particles in argon plasmas have been measured. Angular dissymmetry laser light scattering indicates that larger particles tend to segregate towards the anodic plasma‐sheath boundary; however, the larger particles (≳400 nm diameter) near this boundary are present in number densities lower than those closer to the center of the discharge, where particles are smaller (∼300 nm). Nonspherical particle aggregates appear to form near the plasma‐sheath interface under some conditions. Optical emission intensity and positive ion number density are reduced in discharges with particles as compared to discharges without particles.

ISSN:0003-6951    

DOI:10.1063/1.103946

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Using a Monte Carlo simulation, we show how electron confinement allows sputtering magnetrons to operate at lower neutral pressures than similar unmagnetized devices. We find that at both high and low pressures, the ionization efficiency in a magnetron is constant, and it varies by only 40% between the two regimes. In contrast, the efficiency of an unmagnetized discharge varies linearly with pressure, becoming very small at low pressures.

ISSN:0003-6951    

DOI:10.1063/1.103947

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

A novel soft x‐ray source for submicron resolution lithography is described. Exploratory experiments with thex‐pinch dense plasma radiation source have been performed using a 500 kA, 40 ns pulsed power generator. About 33 J of magnesiumK‐shell radiation (1.3–1.5 keV) and 10 J of aluminumK‐shell radiation (1.6–1.7 keV) have been produced in a source approximately 0.5 mm or less in diameter during a single pulse. The yield increased rapidly with current, implying the possibility of exposing a resist at a distance of 40 cm using a<750 kA pulser in as few as ten pulses.

ISSN:0003-6951    

DOI:10.1063/1.103948

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

L‐ andM‐shell x‐ray spectra obtained when solid targets were irradiated by single, 3.5 ps, KrF laser pulses with irradiances above 1016W cm−2are presented. Modeling of the experimental conditions with a one‐dimensional hydrocode and time‐dependent atomic physics is shown to be consistent with the experimental results.

ISSN:0003-6951    

DOI:10.1063/1.103949

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

An atomic force microscope capable of measuring, simultaneously yet separately, lateral (‘‘frictional’’) and normal forces is described. A direction‐dependent feature, absent in topological images, is found when scanning stepped surfaces of NaCl (001) in ultrahigh vacuum. A simple model is presented to account for this observation.

ISSN:0003-6951    

DOI:10.1063/1.103950

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Low‐pressure chemical vapor deposition of Si1−xGexalloys in a cold wall, lamp‐heated rapid thermal processor was studied. Alloys were deposited using the reactive gases GeH4and SiH2Cl2in a hydrogen carrier gas. The depositions were performed at a total pressure of 2.5 Torr and at temperatures between 500 and 800 °C using GeH4:SiH2Cl2ratios ranging from 0.025 to 1.00. Results showed that Si1−xGexalloys can be deposited selectively on silicon in SiO2. The selectivity is enhanced significantly by the addition of GeH4in the gas stream. In this work, selective depositions were obtained when the GeH4:SiH2Cl2gas flow ratio was greater than 0.2 regardless of the deposition temperature, corresponding to a Ge content of 20% or higher in the films as determined by Auger electron spectroscopy. An enhancement in the deposition rate was observed in agreement with earlier reports due to the addition of GeH4. The activation energy for deposition in the surface reaction limited regime varied from 20 to 30 kcal/mole with the gas flow ratios used in this study.

ISSN:0003-6951    

DOI:10.1063/1.103951

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Ultraviolet/Oxygen (UV/O2) based vapor phase cleaning of Si(100) surfaces dosed with specific organic molecules has been studied by surface and gas phase analytical techniques. The treatment results in chain scission and carbon volatilization as CO and CO2. At room temperature partial trapping of carbon‐containing species in the oxide is observed, while at elevated temperatures complete hydrocarbon removal occurs. UV/O2‐cleaned samples closely resemble those produced by the standard RCA clean in terms of hydrocarbon removal and oxide formation and this process appears suitable as vapor phase final Si wafer clean.

ISSN:0003-6951    

DOI:10.1063/1.103952

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Very high sensitivity to low dose implantation damage has been achieved by a novel quantitative analysis of electron channeling patterns (ECPs). An algorithm, based on the statistical analysis of the two‐dimensional ECP pictures obtained from a scanning electron microscope, has been developed. The analysis yields a single number (the variance), analogous to the quantity &khgr;mindeduced from ion channeling measurements, which characterizes the surface crystallinity. Measurements performed on implanted silicon (point defects) and CdTe (extended defects) crystals show that electron channeling is approximately two orders of magnitude more sensitive to implantation damage than ion channeling. Changes in the ECP of Si and CdTe were observed after implantations with 200 keV Ar and 320 keV In ions at doses as low as 1×1012cm−2and 1×1013cm−2, respectively. Moreover, electron channeling is capable of probing areas about four orders of magnitude smaller than commonly used ion channeling.

ISSN:0003-6951    

DOI:10.1063/1.103953

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The AlAs/GaAs fractional superlattice in an AlGaAs/GaAs modulation‐doped structure, which is used for quantum wire transistors and electron wave interference transistors, is investigated from the viewpoint of the electronic state. A threshold voltage (Vth) difference of 0.27 V between the quantum wire and electron wave interference transistor indicates a periodic potential amplitude of 10 meV.Vthof both these transistors and the flatband voltage (Vfb) calculated from the gate capacitance are obtained at various temperatures between 4.2 and 100 K. The density of states (DOS) is determined from the temperature dependence forVthof both transistors andVfb. A DOS below the bottom of the well in the periodic potential is one dimensional, but a DOS between the bottom of the well and the top of the barrier in the periodic potential is two dimensional.

ISSN:0003-6951    

DOI:10.1063/1.103954

出版商:AIP    

年代:1990

数据来源: AIP