Method for producing semiconductor device

A method for producing a semiconductor device comprising the steps of:

• forming a semiconductor film on an insulating surface;
• disposing a catalyst material in contact with said semiconductor film, said catalyst material being capable of promoting crystallization of said semiconductor film;
• heating said semiconductor film provided with said catalyst material so that said semiconductor film is crystallized throughout its thickness;
• removing said catalyst material from said semiconductor film after the step of heating;
• heating said semiconductor film after said removing step;
• and then
• patterning said semiconductor film in order to form an active layer of a thin film transistor.

A method for producing a semiconductor device comprising the steps of:

• forming a semiconductor film on an insulating surface;
• disposing a catalyst material in contact with said semiconductor film, said catalyst material being capable of promoting crystallization of said semiconductor film;
• heating said semiconductor film provided with said catalyst material so that said semiconductor film is crystallized throughout its thickness;
• removing said catalyst material from said semiconductor film after the heating step;
• irradiating said semiconductor film with laser light or intense light after the step of removing;
• heating said semiconductor film after said removing step;
• and then
• patterning said semiconductor film in order to form an active layer of a thin film transistor.

A method for producing a semiconductor device comprising the steps of:

• forming a semiconductor film on an insulating surface;
• introducing a metal element being capable of promoting crystallization of silicon into said semiconductor film;
• heating said semiconductor film introduced with said metal element so that said semiconductor film is crystallized throughout its thickness;
• removing said metal element from said crystallized semiconductor film;
• and then
• irradiating said crystallized semiconductor film with laser light or intense light,
• wherein said heating step and said irradiating step are repeated at least two times.

A method for producing a semiconductor device comprising the steps of:

• forming a semiconductor film on an insulating surface;
• disposing a catalyst material in contact with said semiconductor film, said catalyst material being capable of promoting crystallization of said semiconductor film;
• heating said semiconductor film provided with said catalyst material in order to crystallize said semiconductor film throughout its thickness;
• removing said catalyst material from said semiconductor film after the step of crystallizing;
• and then
• irradiating said semiconductor film with laser light or intense light,
• wherein said laser light or said intense light is irradiated a plurality of times, and an energy density in said light is gradually increased.

A method for producing a semiconductor device comprising the steps of:

• forming a semiconductor film on an insulating surface;
• disposing a catalyst material in contact with said semiconductor film, said catalyst material being capable of promoting crystallization of said semiconductor film;
• heating said semiconductor film provided with said catalyst material to obtain a crystalline semiconductor film crystallized throughout its thickness after the disposing step;
• removing the catalyst material from the crystalline semiconductor film after said heating step;
• and
• irradiating the crystalline semiconductor film with laser light or intense light after the removing step,
• wherein said step of heating is performed at 450.degree. to 600.degree. C. for about four hours.