Schott Ag

Peter Blaum

Ulrich Peuchert

Burkhard Speit

Wolfram Beier

Yvonne Menke

Mark J Davis

Yoshio Okano

Paula Vullo

Katherine Ann Gudgel

Ingo Koehler

Bernd Ruediger

A transparent, polycrystalline ceramic is described. The ceramic comprises crystallites of the formula ACBDEF, whereby A and C are selected from the group consisting of Li, Na, Be, Mg, Ca, Sr, Ba, Al, Ga, In, C, Si, Ge, Sn, Sc, Ti, Zn, Zr, Mo, Ru, Pd, Ag, Cd, Hf, W, Re, Os, Ir, Pt, Hgand mixtures thereof, B and D are selected from the group consisting of Li, Na, K, Mg, Al, Ga, In, Si, Ge, Sn, Sc, Ti, Zn, Y, Zr, Nb, Ru, Rh, La, Lu, Gdand mixtures thereof, E and F are selected mainly from the group consisting of the divalent anions of S, Se and O and mixtures thereof, x, u, y, v, z and w satisfy the following formulae0.125&#x3c;()/()&#x2266;0.55=4and at least 95% by weight of the crystallites display symmetric, cubic crystal structures of the spinel type, with the proviso that when A=C=Mgand B=D=Al, E and F cannot both be O.

Spinel optoceramics

A translucent piezoelectric glass ceramic is disclosed. The glass ceramic is prepared from a precursor glass by a ceraming process, using a temperature gradient to effect the precipitation of non-ferroelectric piezo-active crystallites from the precursor glass with a preferred direction of orientation and having an average crystal size of less than 1 micrometer. Alternatively, a translucent piezoelectric glass ceramic comprising ferroelectric crystallites may be prepared by poling. In this case the crystal size is controlled to be smaller than 90 nanometers but preferably larger than 10 nanometers.

Translucent piezoelectric glass ceramic

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

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Bodenheim, Germany

Peter Blaum