Siltronic Ag

Wacker Siltronic Gesellschaft F&uuml;r Halbleiter Materialien Ag

Akiyoshi Tachikawa

Atsushi Ikari

Kazunori Ishisaka

A silicon semiconductor substrate has a structure possessing oxygen precipitate defects fated to form gettering sites in a high density directly below the defect-free region of void type crystals. The silicon semiconductor substrate is formed by heat-treating a silicon semiconductor substrate derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method and characterized by satisfying the relational expression (Oi DZ)&#x2212;(COP DZ)&#x2266;10 &#x3bc;m wherein Oi DZ denotes a defect-free zone of oxygen precipitate crystal defects and COP DZ denotes a region devoid of a void type defect measuring not less than 0.11 &#x3bc;m in size, and having not less than 5&#xd7;10oxygen precipitate crystal defects per cm. The method for making the substrate comprises the steps of deriving a silicon semiconductor substrate from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method using molten silicon containing not less than 5&#xd7;10atoms and not more than 1.5&#xd7;10atoms of nitrogen per cmand heat-treating the silicon semiconductor substrate in a non-oxidizing atmosphere at a highest final temperature of not lower than 1150&#xb0; C. for not less than one hour.

Silicon semiconductor substrate and preparation thereof

A semiconductor substrate after heat-treatment in a non-oxidising atmosphere has the characteristics that the depth of the denuded zone may be greater than 12 &mgr;m or the defect-free depth of the void type defect is greater than 12 &mgr;m and the substrate has a locally densified portion produced by nitrogen segregation and exhibiting a signal strength two or more times the average signal strength at the depth of 12 &mgr;m or more below the surface thereof when measuring the concentration of nitrogen by using secondary ion mass-spectroscopy, and the density of the crystal defect of oxygen precipitates is 5&times;10 /cm or more, and the said substrate is produced by heat-treating for at least one hour at the temperature of 1200&deg; C. or more in a non-oxidising atmosphere.

Silicon semiconductor substrate and process for producing the same

A silicon semiconductor substrate which realizes a defect-free region of void type crystals to a greater depth and allows the duration of production to be decreased and a method for the production thereof are provided. A silicon semiconductor substrate derived from a silicon single crystal grown by the Czochralski method or the magnetic field-applied Czochralski method, which is obtainable by using a silicon semiconductor substrate satisfying the relational expression, 0.2&gE;V/S/R, providing V denotes the volume of void type defects, S denotes the surface area thereof, and R denotes the radius of spherical defects presumed to have the same volume as the void defects having the volume of V, and heat treating this substrate at a temperature exceeding 1150&deg; C.

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Yamaguchi, Japan

Akiyoshi Tachikawa