Siltronic Ag

Masamichi Ohkubo

Katsuhiko Nakai

Hideo Kato

Atsushi Ikari

Shinichi Kyufu

Hikaru Sakamoto

Single crystal silicon ingots are grown by the multi-pulling method in a single crucible with minimization of dislocations by incorporating barium as a quartz crystallization inhibitor in amounts proportional to the diameter of the Czochralski crucible in which the crystal is grown. In at least one of the crystal pulling steps, a magnetic field is applied.

Method for manufacturing single-crystal silicon

Silicon single crystal substrates having uniform resistance, few BMDs in a surface layer and a moderate number of BMDs in a center of thickness of the substrate are formed from Czochralski silicon single crystals. The substrates have a resistivity in the center of a first main surface not lower than 50 &#x3a9;&#xb7;cm and a rate of change in resistivity in the first main surface not higher than 3%, an average density of bulk micro defects in a region between the first main surface and a plane at a depth of 50 &#x3bc;m of less than 1&#xd7;10/cm, and an average density of bulk micro defects in a region lying between a plane at a depth of 300 &#x3bc;m and a plane at a depth of 400 &#x3bc;m from the first main surface not lower than 1&#xd7;10/cmand not higher than 1&#xd7;10/cm.

Silicon single crystal substrate and method of manufacturing the same

P-type silicon single crystals from which wafers having high resistivity, good radial uniformity of resistivity and less variation in resistivity can be obtained, are manufactured by the Czochralski method from an initial silicon melt in which boron and phosphorus are present, the boron concentration is not higher than 4E14 atoms/cmand the ratio of the phosphorus concentration to the boron concentration is not lower than 0.42 and not higher than 0.50.

Method of manufacturing silicon single crystal, silicon single crystal, and wafer

Annealed wafers having reduced residual voids after annealing and reduced deterioration of TDDB characteristics of an oxide film formed on the annealed wafer, while extending the range of nitrogen concentration contained in a silicon single crystal, are prepared by a method wherein crystal pulling conditions are controlled such that a ratio V/G between a crystal pulling rate V and an average axial temperature gradient G is &#x2267;0.9&#xd7;(V/G)and &#x2266;2.5&#xd7;(V/G), and hydrogen partial pressure is &#x2267;3 Pa and &#x2266;40 Pa. The silicon single crystal has a nitrogen concentration of &#x3e;5&#xd7;10atoms/cmand &#x2266;6&#xd7;10atoms/cm, a carbon concentration of &#x2267;1&#xd7;10atoms/cmand &#x2266;9&#xd7;10atoms/cm, and heat treatment is performed in a noble gas atmosphere having an impurity concentration of &#x2266;5 ppma, or in a non-oxidizing atmosphere.

Method of manufacturing annealed wafer

Silicon wafers having excellent voltage resistance characteristics of an oxide film and high C-mode characteristics are derived from single crystal silicon ingots doped with nitrogen and hydrogen, characterized in that a plurality of voids constituting a bubble-like void aggregates are present &#x2267;50% relative to total voids; a Vregion having a void density of over 2&#xd7;10/cmand below 1&#xd7;10/cmis &#x2266;20% of the total area of wafer; a Vregion having a void density of 5&#xd7;10to 2&#xd7;10/cmoccupies &#x2267;80% of the total area of the wafer; and bulk microdefect density is &#x2267;5&#xd7;10/cm.

Silicon wafer and method for producing the same

Silicon wafers doped with nitrogen, hydrogen and carbon, have a plurality of voids, wherein 50% or more of the total number of voids are bubble-like shaped aggregates of voids;

Single crystalline ingots can be stably pulled free from dislocation and with a good crystal shape by actuating a crystal driving unit so as to immerse a seed crystal in a silicon melt, and controlling the crystal driving unit and a crucible driving unit under predetermined conditions so as to pull the seed crystal. During pulling, a horizontal magnetic field positioning device applies a magnetic field in the horizontal direction to the inside of the silicon melt, fixing the magnetic field axis at a constant position from the liquid surface of the melt. Positional adjustment of the vertical position of the horizontal magnetic field is performed in advance by a magnetic field position adjusting device, and the magnetic field axis of the applied field is fixed at a constant distance lower than the liquid surface of the melt by more than 50 mm and at the same level or higher than a depth L from the melt surface at the point of tail-in.

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Yamaguchi, Japan

Masamichi Ohkubo