Mitsubishi Materials Silicon Corporation

Mitsubishi Materials Corporation

Other

Mistsubishi Material Corporation

Norihisa Machida

Yoshiaki Arai

Keisei Abe

Hisashi Furuya

A system for growing high-quality, low-carbon-concentration single crystals which have an excellent gas-flow guiding function near the melt, containing 1) an inverted conical, flow-guide cover placed above and coaxially with a double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the single crystal to be grown and the inner surface of the sidewall of the inner crucible; 2) a short passage comprising a hole passing through the sidewall of the inner crucible at a position higher than the level of the melt; and 3) a flow guide cylinder placed above and coaxially with the double-walled crucible, with its lower end located immediately above the surface of the melt and in the space between the outer surface of the sidewall of the inner crucible and the inner surface of the sidewall of the outer crucible, all arranged in a furnace.

Semiconductor single-crystal growth system

Method for growing a semiconductor single-crystal

Thermal stress at a point portion of a seed crystal generated when the seed crystal is brought into contact with molten silicon liquid is relieved, thereby to prevent generation of dislocation, to curtail the time of a seed contraction process and to surely support a heavy weight single crystal. A seed crystal of a silicon single crystal used when the single crystal is grown from molten silicon liquid by a Czochralski method is formed to show the heat emissivity of 0.5 or higher and lower than 1.0 at the point portion of the seed crystal. The point portion of the seed crystal is either a part or the whole of the portion that makes contact with the molten silicon liquid or a portion that makes contact with the molten silicon liquid and a portion that makes no contact with the molten silicon liquid in the vicinity of that portion. It is desirable to form at least 16 lines per 1 cm.sup.2 of fine grooves each having a width of 0.3 to 1.0 mm on the surface of the point portion of the seed crystal, to form microscopic irregularity on the surface of the point portion by sandblasting the surface of the point portion of the seed crystal, or to form a SiO.sub.2 film on the surface of the point portion by applying oxidizing treatment to the surface of the point portion of the seed crystal.

Seed crystal of silicon single crystal

There is provided a double crucible for growing a silicon single crystal in which the partition wall 17 in the shape of ring is concentric with the main crucible 6 in the shape of bottomed cylinder and the lower end of the partition wall 17 is fixed on the inner bottom of the main crucible, and thus the outer crucible 18 and the inner crucible 19 are formed inside the main crucible. The partition wall 17 is uniform in thickness and has introducing holes 20 in its lower part which link the outer crucible with the inner crucible. The partition wall is made so that the inner diameter of its lower part may be smaller than the inner diameter of its upper part. Supposing that A is the diameter of the partition wall at a level of molten silicon, h is a depth from the surface of the molten silicon to the introducing holes, V(out) is an amount of molten silicon stored in the outer crucible, and V(in) is an amount of molten stored in the inner crucible, the relation of D/A=1.5 to 3, 2h/A&gt;1, and V(out)/V(in)=0.4 to 0.9, is satisfied. The invention reduces the number of coarse COPs of 0.3 .mu.m or greater in diameter generated after Sc-1 cleaning on the surface of a silicon wafer made of a single crystal bar grown without making larger in size the furnace of a silicon single crystal continuously growing apparatus.

Double crucible for growing a silicon single crystal

Growing community of inventors

Omiya, Japan

Norihisa Machida