Schott Glaswerke

Schott Glas

Schott Ag

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Schott Glas Mainz

Burkhard Speit

Ludwig Ross

Volkmar Geiler

Peter Brix

Frank-Thomas Lentes

Franz Ott

Georg Gliemeroth

Hans-Georg Krolla

Silke Wolff

Karl Mennemann

Lothar Meckel

Lutz Parthier

Gunther Wehrhan

Thorsten Doehring

Ewald Moersen

Uwe Eichhorn

Gerhard Westenberger

Joerg Kandler

Simone Monika Ritter

Uwe Kolberg

Eric Eva

Wolfram Beier

Dirk Sprenger

Danuta Grabowski

Jörg Hinrich Fechner

Magdalena Winkler-Trudewig

Monika Gierke

Michael Thier

Hexin Wang

Joerg Staeblein

Hans-Werner Schock

Harry Bauer

Thure Boehm

Peter Blaum

Hans-Joerg Axmann

Helge Vogt

Hans-Jurgen Hoffmann

Andreas Weisleder

Markus Schweizer

Lorenz Strenge

Christine Köble

Raymund Schäffler

Hans-Josef Paus

Frank Richter

Ansgar Karnehm

Eva Holzel

Eva G Hoelzel

Ingo Koehler

Bernd Ruediger

The space glass has a composition, in wt. % based on oxide content, of: SiO, 5-65; BO, 0-40; AlO, 0-12; PbO, 25-50; NaO 0-8; KO, 0-20; &#x3a3; alkali metal oxides, at least 0.25; and at least 0.1 wt. % of a total amount of three or more doping agents selected from CeO, MoO, BiO, WO, AgO, SnO, SbOand AsO. In addition, it contains one or more of the following doping agents in the following amounts: at most 1 wt. %, CeO; at most 0.02 wt. %, AsO; at most 0.3 wt. %, SbO; and at most 0.5 wt. %, SnO. Light-weight optical systems for space are made from it, because of its high radiation resistance. A preferred process for making space glass includes melting the oxide starting ingredients at 1050&#xb0; C. to 1200&#xb0; C. to form a melt and refining the melt at 1230&#xb0; C. to 1350&#xb0; C.

Lead-containing space glass, its production and its use

The space glasses have a composition, in wt. % based on oxide content, including SiO, 12-45; BO, 0-4; AlO, 0-4; TiO, 0-5; PbO, 50-82; NaO, 0-4; KO, 0-8; and at least 0.1 wt. % of a total amount of at least three doping agents selected from CeO, MoO, BiO, WO, AgO, SnO, SbOand AsO. Light-weight and space-saving optical systems for outer space applications can be made with these space glasses, which have high UV- and VIS-transmittance and high transmittance stability, because of their high radiation resistance based on their dopant content. A preferred process for making the space glass includes melting the above-stated oxide ingredients in a quartz crucible at 1050&#xb0; C. to 1200&#xb0; C. to form a melt and refining the melt at 1230&#xb0; C. to 1350&#xb0; C.

Lead-containing space glass, its production and use

The electronic semiconductor component has a crystalline wafer substrate with an active surface and a semiconductor layer coating the active surface. So that the semiconductor layer has a few surface defects the crystalline wafer substrate is a sapphire or silicon carbide single crystal and the active surface has a pit density of less than 500 pit/cm, preferably less than 100 pit/cm. The polishing method for obtaining the active surface with these pit densities includes polishing with a polishing agent, such as a silicon suspension, and a polishing tool, which is pressed on the active surface with a pressure of preferably from 0.05 to 0.2 kg/cmand moved over the active surface with polishing motions distributed statistically and uniformly over a 360&#xb0; angle during polishing.

Methods for making wafers with low-defect surfaces, wafers obtained thereby and electronic components made from the wafers

A method is described for making low-stress single crystals with a hexagonal crystal structure, which has a crystallographic c-axis perpendicular to a [0001] surface. A single crystal maintained at a temperature under the melting point of the crystal raw material is dipped in a melt of the crystal raw material, whereby a solid-liquid phase boundary is formed. The crystal is subsequently drawn with an upwardly directed drawing motion e.g. by the Czochralski method. The method is characterized by drawing the crystal along the c-axis so that a temperature gradient of at least 30 K/cm is present in the crystal within a centimeter of the solid-liquid phase boundary and by subsequently performing a tempering treatment on the resulting single crystal. The method is especially suitable for corundum crystals, such as sapphire, which are used as substrates for semiconductor components, such as LEDs.

Method of growing hexagonal single crystals and use of same as substrates for semiconductor elements

In the method and apparatus for measuring the position of the phase interface during growth of a crystal from a melt in a crystal growth container according to the VGF method an incident optical signal is propagated to the phase interface between the melt and the crystal through a window () in the container () and a received optical signal reflected from the phase interface () is measured to determine the position of the phase interface. The position of the phase interface is established from the reflected signal by triangulation with a confocal optic system, by interferometric balancing or by transit time of the optical signal. The window () is preferably mounted in a preferably tilted orientation at the end of a tube (), which is immersed in the melt ().

Method and apparatus for measuring the position of a phase interface during crystal growth

A cadmium-free optical steep edge filter comprising I-III-VI compound semiconductor systems of stoichiometric or non-stoichiometric composition, where the I-III-VI compound semiconductors are systems with one or more of the following elements:

Cadmium-free optical steep edge filters

A method of making a fracture-resistant large-size calcium fluoride single crystal is described, which is suitable for an optical component for radiation in the far UV range. The calcium fluoride raw material for the single crystal is first melted and subsequently solidified by cooling the melt to form a single crystal. However the calcium fluoride raw material is doped with from 1 to 250, preferably 1 to 100, ppm of strontium, preferably added as strontium fluoride, and contains from 1 to 10 ppm of sodium as well as up to 100 ppm of other impurities.

Method of making a fracture-resistant calcium fluoride single crystal and its use

The method for determining radiation stability of a crystal to radiation of a working wavelength to be employed in a subsequent application includes taking a first absorption spectrum (A) of a cleaved piece of the crystal with a given thickness (D) over a predetermined wavelength range from a first wavelength (&lgr; ) to a second wavelength (&lgr; ) by means of a spectrophotometer. Then the cleaved piece of the crystal is irradiated with an energetic radiation source so as to form all theoretically possible color centers (saturation). After the irradiating a second absorption spectrum (B) of the cleaved piece of crystal is taken over the same predetermined wavelength range. Then a surface integral of a difference spectrum of the first absorption spectrum and the second absorption spectrum over the predetermined wavelength range is formed and divided by the thickness (D) to obtain a scaled surface integral value. The absorption coefficient &Dgr;k at the working wavelength for the subsequent application is then obtained preferably from the scaled surface integral value for the damage induced by the energetic radiation and a calibration curve relating the absorption coefficient at the working wavelength to the surface integral of the absorption coefficient induced by the energetic radiation.

Method for determination of the radiation stability of crystals

The method for making a uniform, large-size single crystal of calcium fluoride includes placing a single precursor crystal of calcium fluoride in a tempering vessel provided with a cover; introducing calcium fluoride powder into the tempering vessel and subsequently heating the single precursor crystal, preferably in intimate contact with the calcium fluoride powder, in the tempering vessel together with the calcium fluoride powder for two or more hours at temperatures above 1150&deg; C. to temper the precursor crystal and thus form the uniform, large-scale single crystal of calcium fluoride. The uniform large-sized single crystals of calcium fluoride can be used to make improved lens, prism, light-conducting rod, optical window or other optical component for DUV photolithography, steppers, excimer lasers, wafers, computer chips and electronic devices containing the wafers and chips.

Methods for growing large-volume single crystals from calcium fluoride and their uses

Glass for rigid disk substrates

Magnetic disks comprising a substrate and glass materials which are used in the manufacture of hard disc substrates. The glasses can have the following compositions (in per cent by weight on an oxide basis): SiO,10-30, Al,O,0-5, B,O,0-8, Li,O 0-8, Na,O 1-10, with Li,O&plus;Na,O 5-10, K,O 0-3, MgO 5-16, CaO 0-15, with MgO&plus;CaO>15-25, SrO&plus;BaO 0-8, ZrO,0-8, TiO,7-25, La,O,0-10, Nb,O,O,0-10, CeO,0-1, As,O,&plus;Sb,O,&plus;F 0.1-1. These glasses can have high dimensional stability as a result of their high specific modulus of elasticity, to be especially suited for hard disk substrates.

Magnetic disk comprising a substrate

High E-moduli glasses and glass-ceramics are disclosed based on the SiO,&mdash;B,O,&mdash;RO&mdash;R,O&mdash;ZrO,&mdash;TiO,&mdash;Nb,O,&mdash;La,O,system. The chemically pre-stressable glasses are lithium-poor or lithium-free. The glass-ceramics contain from 2 to 9 percent by weight lithium and the predominant crystalline phase is lithium titanate. These glasses and glass-ceramics particularly have a high specific E-modulus.

Glasses and glass-ceramics with high E-moduli

The glasses used for making rigid disk substrates have the following composition (based on the % by weight of the oxides): SiO.sub.2, 40 to 60; Al.sub.2 O.sub.3, 5 to 20; B.sub.2 O.sub.3, 0 to 5; Li.sub.2 O, 0 to 10; Na.sub.2 O, 0 to 12, with the proviso that Li.sub.2 O+Na.sub.2 O 5 to 12; K.sub.2 O, 0 to 5; MgO, 0 to 20; CaO, 0 to 6, with the proviso that MgO+CaO, 4 to 20,SrO+BaO, 0 to 10; Zr.sub.2 O, 0 to 5; TiO.sub.2, 0 to 5; CeO.sub.2, 0 to 1; La.sub.2 O.sub.3, 0 to 10; Fe.sub.2 O.sub.3, 0 to 10; Nb.sub.2 O.sub.5, 0 to 10; V.sub.2 O.sub.5, 0 to 15, with the proviso that TiO.sub.2 +ZrO.sub.2 +La.sub.2 O.sub.3 +Fe.sub.2 O.sub.3 +Nb.sub.2 O.sub.3 +V.sub.2 O.sub.5 .gtoreq.8, As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 +F, 0.1 to 1; or, SiO.sub.2, 10 to 30; Al.sub.2 O.sub.3, 0 to 5; B.sub.2 O.sub.3, 0 to 8; Li.sub.2 O, 0 to 8; Na.sub.2 O, 1 to 10, with the proviso that Li.sub.2 O+Na.sub.2 O, 5 to 10; K.sub.2 O, 0 to 3; MgO, 0 to 12; CaO, 0 to 15, with the proviso that MgO+CaO,10 to 15, SrO+BaO, 0 to 8; Zr.sub.2 O, 0 to 8; TiO.sub.2, 10 to 25; La.sub.2 O.sub.3, 0 to 10; Nb.sub.2 O.sub.5, 10 to 18; V.sub.2 O.sub.5, 0 to 20; CeO.sub.2, 0 to 1; As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 +F, 0.1 to 1. Both types or groups of glasses fulfill the following inequality formulae (1):

The chemically prestressable glass having a low bubble count and bubble size has the following composition in mol %, based on a total amount of oxides present, SiO.sub.2 from 63.0 to 67.5 mol %, Al.sub.2 O.sub.3 from 9.5 to 12.0 mol %, Na.sub.2 O from 8.5 to 15.5 mol %, K.sub.2 O from 2.5 to 4.0 mol %, MgO from 3.0 to 9.0 mol %, sum of CaO+SrO+BaO+ZnO from 0 to 2.5 mol %, TiO.sub.2 from 0.5 to 1.5 mol %, CeO.sub.2 from 0.02 to 0.5 mol %, As.sub.2 O.sub.3 from 0.02 to 0.35 mol %, SnO.sub.2 from 0. to 1.0 mol %, and F.sub.2 from 0.05 to 2.6 mol %, wherein the molar ratio �SiO.sub.2 !/�Al.sub.2 O.sub.3 ! is 5.3 to 6.85, the molar ratio �Na.sub.2 O!/�K.sub.2 O! is 3.0 to 5.6, the molar ratio �Al.sub.2 O.sub.3 !/�K.sub.2 O! is 2.8 to 3.6 and the molar ratio �Al.sub.2 O.sub.3 !/�TiO.sub.2 +CeO.sub.2 ! is 7.6 to 18.5, but, when arsenic-free, SnO.sub.2 is from 0.02 to 1.0 mol % and F.sub.2 is from greater than 0.5 to 2.6 mol %. The invention also includes a safety glass and a hard disk for information storage made from this chemically prestressable glass.

Chemically prestressable aluminosilicate glass and products made

The process for producing a chemically prestressed glass of very high surface quality includes subjecting an Li.sub.2 O-free starting glass from the SiO.sub.2 -Al.sub.2 O.sub.3 -M.sub.2 O-MO system which also contains TiO.sub.2, CeO.sub.2 and F.sub.2 to chemical ion exchange by immersing it in a potassium salt bath at a temperature between 350.degree. C. and 550.degree. C. and at a residence time of between 0.5 and 20 hours to form the chemically prestressed glass. In a preferred embodiment of the process, the potassium salt bath contains a potassium nitrate melt and the glass is polished after prestressing. The chemically prestressed glass is particularly useful for making hard disks.

Process for production of chemically prestressed glass

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Mainz, Germany

Burkhard Speit