Method for fabricating a semiconductor device

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

• disposing a metal containing material in contact with a semiconductor film comprising amorphous silicon for promoting crystallization;
• crystallizing said semiconductor film by a first heat treatment at a first temperature to obtain a crystalline semiconductor film;
• irradiating laser light or intense light to said crystalline semiconductor film to diffuse said metal existing in said crystalline semiconductor film within said crystalline semiconductor film;
• performing a second heat treatment at a second temperature within an oxidizing atmosphere containing a halogen element to getter said metal existing within said crystalline semiconductor film into a thermal oxide film to be formed after t he irradiating step;
• removing said thermal oxide film formed in the second heat treatment;
• and
• forming another thermal oxide film on the surface of a region from which said thermal oxide film has been removed by performing another thermal oxidation,
• wherein said second temperature is higher than said first temperature.

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

• providing a selected portion of a semiconductor film comprising amorphous silicon with a crystallization promoting material which comprises a metal;
• performing a first heat treatment at a first temperature to said semiconductor film to grow crystal in a direction parallel to the film from said selected portion of the semiconductor film;
• irradiating laser light or intense light to diffuse said metal existing in a region in which said crystal has grown;
• performing a second heat treatment at a second temperature within an oxidizing atmosphere containing a halogen element to form a thermal oxide film, thereby, gettering said metal from the crystallized semiconductor film into said thermal oxide film after the irradiating step;
• removing said thermal oxide film;
• and
• forming another thermal oxide film on the surface of a region from which said thermal oxide film has been removed by performing another thermal oxidation,
• wherein said second temperature is higher than said first temperature.

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

• disposing a metal containing material in contact with a semiconductor film comprising amorphous silicon for promoting crystallization;
• crystallizing said amorphous silicon film by a first heat treatment to obtain a crystalline semiconductor film;
• patterning said crystalline semiconductor film to form an active layer of said semiconductor device;
• irradiating laser light or intense light to said active layer;
• removing or reducing said metal existing within said active layer by performing a second heat treatment within an oxidizing atmosphere containing a halogen element after the irradiating step;
• removing a thermal oxide film formed in the second heat treatment;
• and
• forming another thermal oxide film on the surface of said active layer by performing another thermal oxidation,
• wherein said second heat treatment is conducted at a higher temperature than said first heat treatment.

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

• providing a semiconductor film comprising amorphous silicon with a metal containing material for promoting crystallization;
• crystallizing said semiconductor film by a first heat treatment to obtain a crystalline semiconductor film;
• patterning said crystalline semiconductor film to form an active layer of said semiconductor device;
• irradiating laser light or intense light to said active layer;
• removing or reducing said metal existing within said active layer by performing a second heat treatment within an oxidizing atmosphere containing a halogen element after the irradiating step;
• removing a thermal oxide film formed in the second heat treatment;
• and
• forming another thermal oxide film on the surface of said active layer by performing another thermal oxidation
• wherein said active layer has a tapered shape having an angle made between a side thereof and an underlying surface within a range of 20° to 50°,
• wherein said second heat treatment is conducted at a higher temperature than said first heat treatment.

A method of manufacturing a semiconductor device comprising the steps of:

• forming a semiconductor film comprising amorphous silicon on an insulating surface;
• crystallizing said semiconductor film;
• patterning the crystallized semiconductor film;
• treating a surface of the patterned crystallized semiconductor film by an activated mixture gas comprising oxygen an hydrogen to remove an organic substance therefrom;
• forming a gate insulating film on said patterned crystallized semiconductor film.

A method of manufacturing a semiconductor device comprising the steps of:

• forming a semiconductor film comprising amorphous silicon on an insulating surface;
• crystallizing said semiconductor film by heating at a first temperature;
• irradiating said semiconductor film with a laser light;
• and
• oxidizing a surface of said semiconductor film after the crystallization at a second temperature higher than said first temperature after the irradiating step;
• wherein the heating at the first temperature is performed in an atmosphere which contains oxygen at a concentration of 1 ppm or less.

A method of manufacturing a semiconductor device comprising the steps of:

• forming a semiconductor film comprising amorphous silicon over a glass substrate;
• crystallizing said semiconductor film by heating at a first temperature;
• irradiating said semiconductor film with a laser light;
• and
• oxidizing a surface of said semiconductor film after the crystallization at a second temperature higher than a strain point of said glass substrate after the irradiating step;
• wherein the heating at the first temperature is performed in an atmosphere which contains oxygen at a concentration of 1 ppm or less.