International Business Machines Corporation

Wolfgang Alfred Westdorp

William J Patrick

Pavel Smetana

Kyong-Min Kim

Salvatore J Scilla

Hitendra N Ghosh

Ashok Murgai

An improvement in the method and apparatus for growing a semiconductor crystal by the Czochralski technique comprising the steps of applying a rotating transverse magnetic field to molten semiconductor material held in a crucible during the seed crystal pulling and crystal formation step, to cause the molten material to rotate within the crucible, and simultaneously increasing the rotational velocity of the magnetic field during this crystal formation as a function of the length of the crystal pulled from said molten material to thereby vary the rotation rate of the molten material. These steps result in the uniform axial distribution of oxygen in the crystal.

Semiconductor crystal growth via variable melt rotation

An improved method of growing silicon crystals by the Czochralski method to obtain a desired oxygen concentration level with both axial and radial uniformity. A crucible is located within a heater to achieve a given temperature profile which is related to the oxygen concentration, and then raised and rotated at an increasing speed together with a high crystal rotation rate to achieve the uniformity.

Method of controlling oxygen content and distribution in grown silicon

The seed to tail oxygen concentration gradient in silicon crystals, which are drawn from a silicon melt contained in a silica vessel according to the Czochralski process, is controlled by a process employing stop-go crucible rotation to provide fluid shearing at the melt-crucible interface.

Control of oxygen in silicon crystals

The oxygen content of silicon crystals, which are drawn from a silicon melt contained in a silica vessel according to the Czochralski process, is controlled by changing the surface characteristics of the portion of the silica vessel which is in contact with the melt so as to provide an increased oxygen concentration in the melt during the crystal drawing process.

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Hopewell Junction, NY, United States of America

Wolfgang Alfred Westdorp