Shin-etsu Handotai Co., Ltd.

Hiroshi Ohtsuna

Masahiko Baba

Atsushi Iwasaki

A method for detecting a diameter of a single crystal at the time of pulling the single crystal from a silicon melt contained in a crucible according to the Czochralski method, the method including at least: using two cameras placed equidistant from each other as a target diameter upon forming a straight-body portion of the single crystal and face both ends of the diameter of the single crystal in a growth point of the single crystal respectively, to separately capture both of the ends of the growth point of the single crystal from an outside of a furnace, the growth point being a contact point between the single crystal and a melt surface; and detecting the diameter of the single crystal on the basis of the captured images. As a result, diameter detection precision is improved.

Method for detecting diameter of single crystal, single-crystal manufacturing method by using the same and single-crystal manufacturing apparatus

A method for automatically controlling growing a single crystal neck portion by the CZ method, comprising the steps of pulling up a seed crystal (30) at 2 mm/min. for five minutes so as to grow a single crystal 32; next measuring a diameter of the lower end of the crystal; modifying an electric power for heating a melt based on the difference between the measured diameter and a reference value; waiting for five minutes; keeping the electric power constant for 10 minutes with controlling the pulling up speed so as to approach the diameter of the crystal to the reference value and with measuring the pulling up speed repeatedly; and next modifying the power based on the difference between the mean speed and a reference value. The last two steps are repeated alternatively.

Method of automatic control of growing neck portion of a single crystal

Disclosed are a method of and a device for crystal diameter measurement in an apparatus for automatically controlling single crystal growth by the CZ technique. In the diameter measurement method, a growing region of a single crystal 32 is photographed by a camera 38, and an outer diamter Do of a luminous ring image 70 having a luminance above a reference value E is detected from a video signal supplied from the camera 38, the diameter Do thus detected being used for crystal diameter control. The crystal diameter measuring device comprises: a camera 38 for photographing a growing section of a single crystal 32 and supplying a video signal; devices for detecting a maximum video signal value with respect to one scanning line or more; a device for obtaining a reference value E corresponding to the above-mentioned maximum value; devices for binary-coding the video signal in comparison with the reference value E; and a device for detecting the outer diameter Do of a luminous image from a binary image obtained by the binary-coding.

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Sabae, Japan

Hiroshi Ohtsuna