Jenaer Glaswerk Schott & Gen.

Gerd Muller

Glass compositions useful for passivating silicon semiconductor elements or bodies and to semiconductor elements or bodies coated by such glass compositions. The glass compositions are applied onto the surface of the semiconductor in the form of a finely ground powder and thereafter fused on at least a portion of the semiconductor element. The compositions comprise: (A) glass and (B) powdered cordierite in an amount effective to provide a coefficient of thermal expansion of up to 40 .times. 10.sup.-7 /.degree. C for said composition within the temperature range of 20.degree.-300.degree. C. The compositions are compatible with the thermal expansion of the silicon semiconductor and capable of adhering to the silicon in layers greater than 10 .mu.m without the formation of cracks.

Glass composition for passivating semiconductor surfaces

Transparent, colorless glass ceramic having a low coefficient of expansion, a high absorptivity for X-rays and which is useful in dental filling compositions, has the following ingredients, expressed as percent by weight of oxides: SiO.sub.2 40-55%, Al.sub.2 O.sub.3 15-25%, Li.sub.2 O 3-5%, P.sub.2 O.sub.5 3-10%, MgO 0-3%, ZnO 0-5%, ZrO.sub.2 2-7%, Ta.sub.2 O.sub.5 0-7% and La.sub.2 O.sub.3 10-20%.

Glass ceramic as filler in polymerizable dental filling compositions

Colorless, transparent glass ceramic with a linear thermal expansion which is smaller than 15 .times. 70.sup.-.sup.7 /.degree.C in the temperature range from 20.degree. to 300.degree.C, produced from a glass, which has been melted and shaped and thereafter subjected to a heat treatment for the controlled crystallization of innumerable, irregularly oriented, minute crystals of the structural type of .beta.-quartz, characterized in that it has, to at least 85% by weight, the following composition based on oxides:

Transparent glass ceramic with small thermal expansion

Transparent, colorless, particulate glass ceramic having a low coefficient of expansion, a high absorptivity for X-rays and which is useful in dental filling compositions, has the following ingredients, expressed as percent by weight of oxides: SiO.sub.2 40-55%, Al.sub.2 O.sub.3 15-25%, Li.sub.2 O 3-5%, P.sub.2 O.sub.5 3-10%, MgO 0-3%, ZnO 0-5%, ZrO.sub.2 2-7%, Ta.sub.2 O.sub.5 0-7% and La.sub.2 O.sub.3 &gt;12-20%.

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Mainz-Weisenau, Germany

Gerd Muller