Varian Associates

About: Varian Associates is a based out in . It is known for research contribution in the topics: Beam (structure) & Amplifier. The organization has 2160 authors who have published 2591 publications receiving 46002 citations.

Multilayered iii-v photocathode having a transition layer and a high quality active layer

Abstract: A thin III-V photoemitter crystal having a thickness ranging from 1 micron to 5 microns as grown on a III-V substrate. The bandgap was determined in advance by proportioning the constituents of the crystal causing the peak of the response curve to occur at a predetermined energy and absorb incident photons of the desired wavelength. Due to the high quality of the crystal, the electron diffusion length thereof was comparable to the thickness allowing transmission optics to be employed. Lattice mismatch between the active crystal and the base was minimized by a transition layer, or a progression of transition layers, of intermediate composition. The presence of this strain relieving structure permitted the growth of the thin, high quality single crystals having a relatively long electron diffusion length. As a specific example, a 20 micron transition layer of GaAs.90Sb.10 was epitaxially grown on a GaAs substrate. A three micron active layer of GaAs.85Sb.15 was grown over the transition layers. This composition of the active layer exhibited a bandgap energy of 1.17 ev corresponding to an absorption wavelength of 1.06 microns.

Rapid thermal annealing/chemical vapor deposition and integrated processing

Abstract: This volume contains papers presented at the symposium on rapid thermal annealing/chemical vapor deposition and integrated processing. Rapid thermal processing is growing in many directions. The seven sessions presented during this symposium cover recent developments in the traditional RTP subjects such as ion implant annealing in Si and III-V materials, metals processes (silicides and contact alloying), and oxide growth in addition to newer areas of CVD using RTP techniques, integrated processing and complex dielectric structures (such as ONO). Work in all aspects of RTP is progressing and it appears that the integration of rapid thermal processing into manufacturing environments is finally occurring.

PLASMA ETCH PROCESS AND TiSix LAYERS MADE USING THE PROCESS

Abstract: A method for making an improved metal silicide layer on a silicon substrate by plasma bombardment of the substrate with Ne ions toremove the native oxide without damage or significant implantation of Ne atoms into said silicon, depositing a metal layer over Ne etched surface and then rapidly thermally causing the metal layer to react with the underlying silicon is disclosed. The figure shows the TiSi sheet resistance as a function of the preclean plasma etch substrate bias for Xe, Ar, and Ne. The figure shows that the sheet resistance does not vary as a function of the bias voltage for Ne.

Paramagnetic Unit in Spinach Subchloroplast Particles: Estimation of Size

Abstract: A pulsed ruby laser (wavelength, 694.3 nanometers) was used to measure the dependence on light intensity of light-induced electron paramagnetic resonance (ERR) signal 1 for short flashes of uniform duration (400 microseconds). Approximately 10(18) photons per square centimeter per flash from the unattenuated beam were available to the sample of subchloroplast "system 1" particles from spinach. The experimental dependence of the EPR signal height plotted as a function of the total number of incident photons per flash was exponential. From measurement of the slope at a very low relative photon flux and the saturated EPR signal amplitude, the value for the cross section or "effective size" of the light-induced paramagnetic unit, sigma(EPR), was found to be 300 x 10(-17) square centimeter. This result is compared with a measured optical absorption cross section, sigma(694nm), of 2.5 x 10(-17) square centimeter, for the identical sample at the laser wavelength. The hundredfold difference in size supports the thesis that the paramagnetic state is a property of an aggregate of chlorophyll molecules of the same general size as the photosynthetic unit.

Microwave oscillations in high-resistivity GaAs

Abstract: It has been found that Gunn-effect oscillations in high-resistivity GaAs cease when the product of the conduction electron density and the sample length drops below 1011cm-2as predicted by theory. The samples investigated exhibited impact ionization of a deep donor level lying 0.41 eV below the conduction band edge when subjected to an applied electric field equal to the Gunn-effect threshold field. Some observations concerning space-charge limited injection of electrons and concerning electrical breakdown in high-resistivity GaAs are also reported.