Asahi Glass Company, Limited

Yukinori Ohta

Kimihiko Sato

Shinya Kikugawa

Hitoshi Kijimuta

Kunihiko Terase

Susumu Yaba

A quartz glass substrate for polysilicon thin film transistor liquid crystal display, in which a halogen content is not more than 10 ppm; an OH content is not more than 100 ppm; a total content of a heavy metal element and an alkali metal element is not more than 1 ppm; and an annealing point is not less than 1,150.degree. C.

Quartz glass substrate for polysilicon thin film transistor liquid

A method for synthesizing amorphous silicon nitride, wherein silicon halide and ammonia are reacted in a reaction vessel at a high temperature in the absence of oxygen to thereby synthesize powder of amorphous silicon nitride, then the powder is separated from a gas containing therein gaseous ammonia halide which has been produced simultaneously with said amorphous silicon nitride by use of a collecting means, comprises directly mixing, in advance of the separation, cool gas containing therein neither oxygen nor moisture into said gas to cool down said powder and gas so that both substances may be put in said collecting means without deposition of ammonium halide to the inner wall of the reaction vessel, and other component parts.

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Yokohama, Japan

Yukinori Ohta