Komatsu Electronic Metals Co., Ltd.

Komatsu Denshi Kinzoku Kabushiki Kaisha

Yoshiyuki Shimanuki

Toshirou Kotooka

Makoto Kamogawa

Toshimichi Kubota

Hirotaka Nakajima

Hiroshi Inagaki

Kozo Nakamura

Shigeki Kawashima

Toshiaki Saishoji

Shinya Sadohara

Toshiro Kotooka

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

This invention provides a device for manufacturing single crystals provided with an after-cooler that causes an abrupt temperature gradient along the axis of the crystal being lifted. The device according to this invention can further increase the lifting speed of single crystals. The after-cooler (4) is disposed between the single crystal (5) being lifted and the heat-shield plate (1). Both the inner surface facing the single crystal (5) and the outer surface facing the heat-shield plate (1) of the after-cooler have a surface emissivity value larger than 0.6. Furthermore, the after-cooler (4) is made of cooling pipes or cooling jackets, and the surfaces of the after-cooler (4) are treated by oxidizing or nitriding so as to increase their emissivity values.

Device for manufacturing single crystals

An apparatus for fabricating single-crystal silicon easily controlling a temperature gradient based on the Czochralski (CZ) method, and more particularly preventing as-grown defects created in order to obtain high-quality single-crystal silicon. The above-mentioned apparatus includes a first thermal shield member surrounding the pulling single-crystal silicon and a second thermal shield member inside the first thermal shield member, surrounding the pulling single-crystal silicon. The second thermal shield member is fixed on the first thermal shield member by a support located on the external surface of the second thermal shield member and connected to the first thermal shield member. The surroundings of a solid-liquid interface are extremely cooled by using the first thermal shield member, thereby a stable shape of the single-crystal silicon is formed. The temperature gradient of the temperature region of 1000.degree. C..about.1200.degree. C. where the single-crystal silicon passes is decreased by using the second thermal shield member so as to reduce the crystal defect density, thereby obtaining single-crystal silicon having a stronger oxide film voltage breakdown characteristic. If the support length is changed, the second thermal shield member can be adjusted in the upper or lower direction in order to make the expected portion of single-crystal silicon cool slowly.

Apparatus for fabricating single-crystal silicon

This invention provides a single-crystal manufacturing device which can perform the lifting of single crystals at a high speed, allowing single crystals with uniform qualities along their axes can be obtained. The method for manufacturing single crystals according to this invention are achieved by using a single-crystal manufacturing device provided with a combination of a heat shield plate 1 and an after-cooler 21. The heat shield plate 1, the thickness of the lower portion of which is 2-6 times that of a conventional heat shield plate, surrounds the single crystal 7 being lifted. The after-cooler 21 covers the top surface of the rim 1a of the heat shield plate 1 and encompasses the single crystal 7 being lifted. The amount of cooling water supplied to the after-cooler 21 is slowly increased until the time the single crystal is lifted to a preset length, and then the amount of cooling water is kept constant. By this means, the temperature gradients of the single crystal in the region near the solid-liquid boundary can be increased, and the shape of the single crystal lifted can be easily kept unchanged. Furthermore, the lifting speed of the single crystal is kept constant from the top to the bottom of the crystal. Compared with conventional methods, the single-crystal lifting speed can be multiplied by a value of 1.3-2.2. Therefore, single crystals with uniform qualities along their axes can be obtained.

Method and device for manufacturing single crystals

An cylindrical after-heater surrounding a single crystal being lifted and a cylindrical heat-retaining cylinder installed between the after-heater and the single crystal are provided above a reversed frustrated heat-shielding sleeve disposed near the melted liquid. The heat history of the single crystal can be controlled by adjusting the output of the after-heater and the location of the heat-retaining cylinder. By such an arrangement, rapid respond to the change of the heat environment in a furnace can be made and control of the temperature gradient of the single crystal can be achieved. The single crystal, throughout the whole length, is maintained in the range of from 1000.degree. C. to 1200.degree. C. for more than one hour during lifting operation.

Apparatus for manufacturing semiconductor single crystals

This invention provides a method and apparatus for fabricating semiconductor single crystals. By using the method of this invention, the temperature gradient of the single crystal being lifted can be easily controlled. The as-grown defect density can be reduced, and it is possible to manufacture high quality semiconductor single crystals with high oxidation-film breakdown strength. A shield cylinder is used for surrounding the semiconductor single crystal 7 being lifted, the shield cylinder is made to be of the telescopic type and consists of a first shield duct 4, a second shield duct 5, a third shield duct 6. A wire 8 wrapping around a wind-up reel 10 is engaged with the third shield duct 6, and the shield cylinder can be driven to extend or retract by rotating the wind-up reel 10. An ascend and descend rod 3 is connected with the first duct 4, and the shield cylinder can be driven to move upward or downward by lifting or lowering the ascend and descend rod 3. The wind-up reel 10 is driven to retract part of the shield cylinder so that the lapped portion of the shield cylinder keeps a predetermined portion of the semiconductor single crystal 7 being lifted warm, and the temperature gradient of the semiconductor single crystal 7 can be reduced when it passes through the zone whose temperature is within a range from 1000.degree. C. to 1200.degree. C.

Growing community of inventors

Hiratsuka, Japan

Yoshiyuki Shimanuki