Capping technique for zone-melting recrystallization of insulated semiconductor films

A method of forming an encapsulated insulated semiconductor film structure, comprising

• forming a first layer of insulating material on a substrate,
• forming a second layer of amorphous or polycrystalline silicon,
• forming a third layer of silicon dioxide to form a silicon dioxide capped silicon on insulator structure,
• providing an atmosphere consisting essentially of inerts and a noninert gas, stable at ambient temperature, which is a source of a reactive material whose presence promotes wetting of molten silicon on silicon dioxide, said noninert gas decomposing below the melting point of silicon to release said reactive material,
• annealing said structure in said atmosphere at a temperature below the melting point of silicon but high enough to decompose said gas so as to release said reactive material for a sufficient length of time to diffuse quantities of said reactive material through the third layer to the interface with the second layer in an amount sufficient to avoid agglomeration of the resulting semiconductor film, and
• subjecting the annealed structure resulting from the preceding steps to zone melting recrystallization.

A method of forming an encapsulated insulated semiconductor film body, comprising

• forming an insulating layer on a substrate,
• forming a semiconductor layer of amorphous or polycrystalline silicon on top of the insulating layer,
• forming a capping layer of silicon dioxide on top of the semiconductor layer to a partial thickness to form a silicon dioxide capped silicon on insulator structure,
• providing an atmosphere consisting essentially of inerts and a noninert gas, stable at ambient temperature, which is a source of a reactive material whose presence promotes wetting of molten silicon on silicon dioxide, said noninert gas decomposing below the melting point of silicon to release said reactive material,
• annealing said structure in said atmosphere at a temperature below the melting point of silicon but high enough to decompose said gas so as to release said reactive material for a length of time sufficient for the reactive material to diffuse through the partial thickness of the capping layer to the interface with the semiconductor layer to avoid agglomeration of the resulting semiconductor film,
• increasing the thickness of the capping layer by forming an additional integral layer of the same material, and
• subjecting the structure formed by the preceding steps to zone-melting recrystallization.