Siltronic Ag

Nippon Steel Corporation

Yutaka Kishida

Teruyuki Tamaki

Seiki Takebayashi

Wataru Ohashi

Hideo Kato

Masahiro Tanaka

In silicon single crystal growth by the Czochralski method using a quartz crucible, a silicon single crystals with a uniform distribution of oxygen concentration can be produced in high yield without being affected by changes of crystal diameter and initial amount of melt feedstock. The oxygen concentration is adjusted by estimating oxygen concentration during growth on the basis of a relationship among three parameters: crucible rotation rate (&#x3a9;), crucible temperature (T), and the ratio (&#x3b2;) of contact area of molten silicon with the inner wall of the crucible and with atmospheric gas, and by associating the temperature (T) with the ratio (&#x3b2;) by the function 1/&#x3b2;&#xd7;Exp(&#x2212;E/T) where E is the dissolution energy (E) of quartz into molten silicon to control at least one of the rotation rate (&#x3a9;) and temperature (T) to conform the estimated oxygen concentration to a target concentration.

Silicone single crystal production process

A crucible for the growth of single crystals by the Czochralski method which can enhance the productivity, yield and quality of crystal and a single crystal growing method, wherein the crucible has an inner bottom surface, the profile of which has at least one raised portion symmetrical about the rotary axis of the crucible wherein the periphery of the raised portion is positioned at a distance of from 0.4 to 1.2 times the radius of crystal to be grown from the rotary axis and the height of the raised portion is generally not smaller than 7% and greater than 100% of the radius of crystal to be grown.

Crucible for the growth of silicon single crystal and process for the growth thereof

A single crystal production method based on the Czochralski method comprises controlling a number of crucible rotations and crystal rotations so that a number of vibrations for driving a melt, determined on the basis of the number of crucible and crystal rotations during a single crystal growing procedure, is outside a range from 95% to 105% of a number of sloshing resonance vibrations of the melt. In another embodiment, the method comprises controlling a number of rotations of a crystal and crucible, so that when a number of vibrations for driving a melt, determined by the number of crucible and crystal rotations during a single crystal growing procedure, is within a range from 95% to 105% of a number of sloshing resonance vibrations of the melt, the number of vibrations of the melt due to sloshing does not exceed 2000 times during a period when the number of vibrations is within that range.

Single crystal production method

In the manufacture of a silicon single crystal by the Czochralski method, there is provided a seed crystal for use in the production of the silicon single crystal. This seed crystal is capable of preventing creation of a dislocation occurring during the immersion of the seed crystal in the molten silicon and withstanding the load of a silicon single crystal of great weight as well. There is also a method for the production of the seed crystal and a method for the production of a silicon single crystal which enables the ratio of elimination of dislocation to be increased. A seed crystal for the production of a silicon single crystal for use in the manufacture of a silicon single crystal by the Czochralski method, has the boron concentration in the silicon single crystal as the matrix from which the silicon seed crystal is excised is not less than 4&times;10 atoms/cm and not more than 4&times;10 atoms/cm and the silicon seed crystal is excised from the silicon single crystal as the matrix, ground, and lapped, and subsequently subjected to surface etching.

Seed crystal for production of silicon single crystal and method for production of silicon single crystal

In the growth of a large silicon single crystal weighing not less than 100 kg by the Czokralski method resorting to application of a magnetic field, a crucible, not less than 0.7 m in inside diameter is used, and a cusped magnetic field which manifests a maximum intensity of not more than 1000 gausses on the inner wall of the crucible is applied.

Growing community of inventors

Yamaguchi, Japan

Yutaka Kishida