Semiconductor device and fabrication method thereof

A method for fabricating a semiconductor device, comprising steps of:

• intentionally introducing a metal element which promotes crystallization of silicon to a semiconductor film comprising amorphous silicon and crystallizing said semiconductor film by a first heat treatment to obtain a crystalline semiconductor film;
• eliminating or reducing said metal element existing within said crystalline semiconductor film by implementing a second heat treatment within an oxidizing atmosphere to form a thermal oxide film on the surface of said crystalline semiconductor film and by causing said thermal oxide film to getter said metal element;
• eliminating said thermal oxide film formed in the previous step;
• and
• forming a thermal oxide film on the surface of a region from which said thermal oxide film has been eliminated by implementing another thermal oxidation.

A method for fabricating a semiconductor device, comprising steps of:

• intentionally introducing a metal element which promotes crystallization of silicon to a semiconductor film comprising silicon and crystallizing said semiconductor film by a first heat treatment to obtain a crystalline semiconductor film;
• eliminating or reducing said metal element existing within said crystalline semiconductor film by implementing a second heat treatment within an oxidizing atmosphere;
• eliminating a thermal oxide film formed in the previous step;
• forming an active layer of a thin film transistor by implementing patterning;
• and
• forming a thermal oxide film which constitutes at least a part of a gate insulating film on the surface of said active layer by means of thermal oxidation.

A method for fabricating a semiconductor device, comprising steps of:

• selectively introducing a metal element which promotes crystallization of silicon to a semiconductor film comprising;
• growing crystal by a first heat treatment in a direction parallel to the film from the region to which said metal element has been selectively introduced;
• forming a thermal oxide film on the surface of the region where said crystal has been grown by implementing a second heat treatment within an oxidizing atmosphere;
• eliminating said thermal oxide film;
• and
• forming an active layer of said semiconductor device by using the region from which said thermal oxide film has been eliminated.