Process and apparatus for producing polycrystalline semiconductor
AssigneeSharp Kabushiki Kaisha
InventorTetsuhiro Okuno
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Abstract
A process and apparatus for producing a high-quality polycrystalline semiconductor ingot with excellent crystallographic properties are disclosed. The interior of an airtight vessel is kept in an inert atmosphere for semiconductors. A raw semiconductor material is charged in a crucible, and the raw semiconductor material is heated by an induction heating coil so as to be melted. Then the bottom of the crucible is deprived of heat for causing the raw semiconductor material to solidify, thereby producing a polycrystalline semiconductor. The semiconductor crystal grows in one direction from the bottom to the top of the crucible while the heat emission is changed in accordance with a predetermined relationship for keeping the solidification rate of the raw semiconductor material constant.
Claims21
A process for producing a polycrystalline semiconductor comprising the steps of:
- charging a raw semiconductor material into a crucible in an atmosphere inert to the semiconductor;
- heating and melting the raw semiconductor material in the crucible by heating means;
- solidifying the melted raw semiconductor material while depriving the bottom of the crucible of heat;
- and then
- cooling the solidified semiconductor while cooling the crucible,
- wherein a relationship between heat emission and solidification rate at which rate a solid-liquid interface of the raw semiconductor material moves is previously determined, and
- when solidifying the melted raw semiconductor material, a heat emission is changed with time according to the predetermined relationship so as to keep the solidification rate constant.
An apparatus for producing a polycrystalline silicon semiconductor comprising:
- an airtight vessel capable of keeping therein an atmosphere inert to the semiconductor;
- a crucible arranged in the airtight vessel, into which a raw semiconductor material is charged;
- heating means for heating the crucible at upper portions of a bottom of the crucible to melt the raw semiconductor material;
- a supporting bed for mounting the crucible thereon by supporting an under side of the bottom of the crucible;
- cooling means for cooling the supporting bed;
- driving means for driving the supporting bed so as to rotate about a vertical axis, as well as to move up or down;
- and
- heat emission controlling means for controlling a heat emission in accordance with a relationship between solidification rate and heat emission so as to keep the solidification rate constant at the time of solidification of the raw semiconductor material.
Dependencies are inferred from the claim text.