Komatsu Electronic Metals Co., Ltd.

Komatsu Denshi Kinzoku Kabushiki Kaisha

Hirotaka Nakajima

Hiroshi Inagaki

Toshirou Kotooka

Shigeki Kawashima

Yoshiyuki Shimanuki

Takashi Yokoyama

Kozo Nakamura

Makoto Kamogawa

Toshimichi Kubota

Toshiaki Saishoji

Shinya Sadohara

Toshiaki Saishouji

Kouzou Nakamura

Masashi Nishimura

A method for growing a silicon crystal by a Czochralsky method, wherein, let a pulling speed be V (mm/min) and an average value of an in-crystal temperature gradient in a pulling axis direction within a temperature range, a silicon melting point to 1350&#xb0; C., be G (&#xb0; C./mm), V/G ranges from 0.16 to 0.18 mm/&#xb0; C. min between a crystal center position and a crystal outer periphery position, and a ratio G outer/G center of an average value G of an in-crystal temperature gradient in a pulling axis direction within a temperature range, a silicon melting point to 1350&#xb0; C., at a crystal outer surface to that at a crystal center is set to up to 1.10 to thereby obtain a high-quality perfect crystal silicon wafer. Such a perfect crystal silicon wafer, wherein an oxygen concentration is controlled to up to 13&#xd7;10atoms/cm, an initial heat treatment temperature is at least up to 500&#xb0; C. and a temperature is raised at up to 1&#xb0; C./min at least within 700 to 900&#xb0; C., thereby making uniform a wafer radial distribution to an arbitrary oxygen precipitation density level.

Production method for silicon single crystal and production device for single crystal ingot, and heat treating method for silicon crystal wafer

There are provided a system for manufacturing a single-crystal ingot which is equipped with a cooler for cooling the single-crystal ingot being pulled and is capable of forming a tail without involvement of excessive heating of a crucible, as well as to a method for controlling the system. In a system for manufacturing a single-crystal ingot having a cooler for cooling a single-crystal ingot which is being pulled from molten raw material (called a single-crystal pulled ingot), when a tail of the single-crystal pulled ingot is formed, the cooler is moved away from the solid/melt interface between the single-crystal ingot and the molten raw material, to thereby reduce the power dissipated by the system. In the system, the cooler is moved upward after the end of a product area of the single-crystal ingot has been cooled until it passes through a grown-in defect temperature range.

Method and apparatus for manufacturing single-crystal ingot

The cooling speed of the portion near the rear part of a single-crystal body and passing through the defect-forming temperature zone is kept the same as that of the front portion of the single-crystal body. Namely, the heater is kept in operation while pulling the single crystal silicon subsequent to forming the tail of the single crystal silicon and the cooling speed throughout the whole single-crystal body in the defect-forming temperature zone is kept below 15.degree. C./min (levels A and B). Furthermore, the length of the tail is preset in the process of pulling the single crystal silicon so that the single-crystal body cools down slowly while passing through the defect-forming temperature zone (level C). In addition, the temperature of the portion near the rear part of the single-crystal body under pulling is below the minimum temperature of the defect-forming temperature zone by shortening the distance between melted liquid surface and the portion passing through the defect-forming temperature zone of the single-crystal, and by increasing the temperature gradient along the single-crystal axis (level D).

Method of fabricating a silicon single crystal

A method for fabricating a semiconductor single crystal by the MCZ method by which it is possible to pull large diameter and heavy semiconductor single crystals without breaking the contraction portion, is provided. In the contracting step, change the shape of the crystal growth interface by making the range of the temperature fluctuation caused by convection in the vicinity of the melt surface more than 5.degree. C. so as to eliminate the dislocation in the contracted portion. When a transverse magnetic field is applied by magnets 6,6, the magnetic field intensity is set below 2000 Gauss to properly change the shape of the crystal growth interface to form the contracted portion 10. Thus,even though the diameter of the contracted portion 10 is larger than normal, free dislocation is achieved. After the dislocation is eliminated, the magnetic field intensity is recovered and shoulder 11 is formed. When a cusp magnetic field is applied, the contracting is performed when the magnetic field intensity of one of the upper-and-lower magnets being increased while the magnetic field intensity of another magnet is decreased or the upper-and-lower magnets are moved in a vertical direction to make the vicinity of the melt surface similar to a longitudinal magnetic field. After dislocation is eliminated, the magnetic field intensity of the upper-and-lower magnets or the position of the magnets is recovered.

Magnetic field-applied fabrication method for a semiconductor single

Growing community of inventors

Hiratsuka, Japan

Hirotaka Nakajima