Nippon Telegraph and Telephone Corporation

Hiroki Kohda

Kazuo Fujiura

Masahiro Sasaura

Takashi Kobayashi

Takashi Kurihara

Tadayuki Imai

Highly-qualified crystals are grown with good yield under an optimal temperature condition by controlling the axial temperature distribution in the vicinity of the seed crystal locally. In an apparatus for producing crystals to grow crystals wherein a seed crystalis placed in a cruciblewhich is retained in a furnace, raw materialsfilled in the crucibleare heated and liquefied, and a raw materialslowly cooled in the cruciblefrom below upward, the apparatus including a temperature controller for controlling temperature to cool or heat the vicinity of the seed crystallocally. The temperature controller controls the temperature by a hollow constructed capmounted outside the portion of crucibleand regulates refrigerant flow running through the hollow portion.

Apparatus for producing crystals

A method and an apparatus for producing crystals wherein crystal quality can be kept and a crystal composition is uniformed from a growth early stage to a growth last stage are provided. In an apparatus for producing crystals wherein the crystalsare grown from a liquefying raw materialin a crucible retained in a furnace and slowly cooling the raw materialin the cruciblefrom below upward, the apparatus comprises a raw material supply apparatuswhich supplies a resupply raw material, and a reflection plateplaced above the crucible, which liquefies the resupply raw materialsupplied from the raw material supply apparatusand drops it as a liquid into the crucible.

Growing community of inventors

Hiratsuka, Japan

Hiroki Kohda