Lateral pulling growth of crystal ribbons

A method of growing a thin single crystal semiconductor ribbon which comprises

• (a) producing a melt of a crystalline semiconductor substance in a container by heating said crystalline substance,
• (b) bringing a seed crystal into contact with said melt and pulling a thin single crystal semiconductor ribbon from an area of the melt inwardly and away from an edge of the container at an angle greater than zero but not greater than 10 degrees upwardly from the horizontal melt surface during a major portion of the pulling, said ribbon having the same crystal structure as said melt of said crystalline substance,
• (c) reducing the temperature in the surface area of the melt to a temperature below the melting point of the melt to form a supercooled layer by cooling said surface area with a gas blowing cooling means which extends over the melt for a given distance measured in the direction of pulling said ribbon, and
• (d) adjusting at least one of (i) said heating of said melt and (ii) the amount of said cooling, to produce a substantially wedge-shaped crystal growing domain located substantially completely under said cooling means and within said given distance, and having a length L from its front leading edge to its back edge B such that the ratio of said length L to the thickness of the resulting ribbons is not less than 50, and pulling said single crystal ribbon at a rate of at least 300 mm/min.

A method of growing a thin single crystal semiconductor ribbon which comprises

• (a) producing a melt of a crystalline semiconductor substance in a container by heating said crystalline substance,
• (b) bringing a seed crystal into contact with said melt and pulling a single crystal semiconductor ribbon substantially laterally from said melt, said ribbon having the same crystal structure as said melt of said crystalline substance,
• (c) reducing the temperature in the surface area of the melt to a temperature below the melting point of the melt to form a supercooled layer by cooling said surface area with a gas blowing cooling means which extends over the melt for a given distance measured in the direction of pulling said ribbon,
• (d) adjusting at least one of (i) said heating of said melt and (ii) the amount of said cooling, to produce a substantially wedge-shaped crystal growing domain located substantially completely under said cooling means and within said given distance, and having a length L from its front leading edge to its back edge B such that the ratio of said length L to the thickness of the resulting ribbon is not less than 50, and pulling said single crystal ribbon at a rate of at least 300 mm/min., and
• (e) adjusting the temperature distribution in the surface area of the melt surrounding the crystal growing domain to above the melting point of the crystal to control the contour of the front edge of the crystal growing domain to a shape in which there are no edge portions advanced in the crystal growth direction from any point on both sides of the front edge divided by the point thereof.

A method of growing a thin single crystal semiconductor ribbon which comprises

• (a) producing a melt of a crystalline semiconductor substance in a container by heating said crystalline substance,
• (b) bringing a seed crystal into contact with said melt and pulling a single crystal semiconductor ribbon substantially laterally from said melt, said ribbon having the same crystal structure as said melt of said crystalline substance,
• (c) reducing the temperature in the surface area of the melt to a temperature below the melting point of the melt to form a supercooled layer by cooling said surface area with a gas blowing cooling means which extends over the melt for a given distance measured in the direction of pulling said ribbon, and
• (d) heating the crystal growing interface with a heating means having a heating surface substantially parallel to the crystal growing interface and located beneath the crystal growing domain at a distance of not more than 30 mm, to produce a substantially wedge-shaped crystal growing domain located substantially completely under said cooling means and within said given distance, and having a length L from its front leading edge to its back edge B such that the ratio of said length L to the thickness of the resulting ribbon is not less than 50, and pulling said single crystal ribbon at a rate of at least 300 mm/min.