Philips

About: Philips is a company organization based out in Vantaa, Finland. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 68260 authors who have published 99663 publications receiving 1882329 citations. The organization is also known as: Koninklijke Philips Electronics N.V. & Royal Philips Electronics.

Native defects and self-compensation in ZnSe.

Abstract: Wide-band-gap semiconductors typically can be doped either n type or p type, but not both. Compensation by native point defects has often been invoked as the source of this difficulty. We examine the wide-band-gap semiconductor ZnSe with first-principles total-energy calculations, using a mixed-basis program for an accurate description of the material. Formation energies are calculated for all native point defects in all relevant charge states; the effects of relaxation energies and vibrational entropies are investigated. The results conclusively show that native-point-defect concentrations are too low to cause compensation in stoichiometric ZnSe. We further find that, for nonstoichiometric ZnSe, native point defects compensate both n-type and p-type material; thus deviations from stoichiometry cannot explain why ZnSe can be doped only one way.

Supported Chromium Catalysts for Ethylene Polymerization

Abstract: Publisher Summary This chapter discusses supported chromium (Cr) catalysts for ethylene polymerization. The Phillips Cr/silica polymerization catalyst is prepared by impregnating a Cr compound onto wide pore silica and then calcining in oxygen to activate the catalyst. This leaves Cr in the hexavalent state, monodispersed on the silica surface. Chromium trioxide (CrO3) has been impregnated most commonly, but even a trivalent Cr salt can be used because oxidation to Cr(VI) occurs during calcining. Dichromate is the main species in CrO3 solutions. Trivalent Cr salts, notably CrCl3, impregnated onto silica and calcined under vacuum, are found to polymerize ethylene. Three processes are used commercially to make linear polyethylene—namely, solution, slurry, and gas phase. All these processes are called “low-pressure processes” to distinguish them from the free radical or high-pressure process that makes highly branched polyethylene. The slurry process is very convenient for batch polymerization studies. The diluent permits precise control of the temperature and serves to dissolve ethylene and other reactants that must contact the catalyst during polymerization.

Plasma and thermal ALD of Al2O3 in a commercial 200 mm ALD reactor

Abstract: The deposition of Al 2 O 3 by remote plasma atomic layer deposition (ALD) in the Oxford Instruments FlexAL reactor was studied and compared with results from thermal ALD in the same reactor. Trimethylaluminum [Al(CH 3 ) 3 ] was used as the metal precursor and O 2 plasma and H 2 O were used as oxidizing agents for the plasma and thermal processes, respectively. For remote plasma ALD with a total cycle time of 4 s, the growth per cycle decreased monotonically with substrate temperature, from 1.7 A/cycle at 25°C to 1.0 A/cycle at 300°C. This growth per cycle was consistently higher than that obtained for thermal ALD. For the latter a maximum growth per cycle of ∼ 1.0 A/cycle was found at 200°C. The film properties investigated were nearly independent of oxidant source for temperatures between 100 and 300°C, with a slightly higher mass density for the remote plasma ALD Al 2 O 3 films. Films deposited at 200 and 300°C were stoichiometric with a mass density of 3.0 g/cm 3 and low C (< 1 atom %) and H (<3 atom %) contents. At lower substrate temperatures, oxygen-rich films were obtained with a lower mass density and higher H-content. Remote plasma ALD produced uniform Al 2 O 3 films with nonuniformities of less than ±2% over 200 mm diam substrates. Excellent conformality was obtained for films deposited in macropores with an aspect ratio of ∼8 (2.0-2.5 μm diam). Preliminary results on electrical properties of remote plasma deposited films showed high dielectric constants of 7.8 and 8.9 for as-deposited and forming gas annealed Al 2 O 3 , respectively.

Wireless power control

Abstract: A remote device in accordance with the present invention includes an adaptive power receiver that receives wireless power from the wireless power supply by induction. The adaptive power receiver may be switched among two or more modes of operation, including, for example, a high-Q mode and a low-Q mode. By controlling the switching between modes, the amount of energy received by the adaptive receiver may be controlled. This control is a form of adaptive resonance control or Q control.