Method for manufacturing semiconductor device

A method for manufacturing a semiconductor device, comprising:

• forming a first semiconductor film on an insulating surface;
• irradiating the first semiconductor film with laser light;
• forming an oxide film at a surface of the first semiconductor film;
• forming a semiconductor film by patterning the first semiconductor film;
• heating the first semiconductor film to form a second semiconductor film;
• oxidizing a surface of the second semiconductor film by using a solution comprising ozone;
• forming a fourth semiconductor film comprising a rare gas element over the second semiconductor film;
• and
• adding an impurity to the second semiconductor film to form source and drain regions.

A method for manufacturing a semiconductor device, comprising:

• forming a first semiconductor film on an insulating surface;
• irradiating the first semiconductor film with laser light;
• forming an oxide film at a surface of the first semiconductor film;
• forming a second semiconductor film by patterning the first semiconductor film;
• heating the second semiconductor film to form a third semiconductor film;
• oxidizing a surface of the third semiconductor film by using a solution comprising ozone;
• heating the third semiconductor film to form a fourth semiconductor film;
• forming a fifth semiconductor film comprising a rare gas element over the fourth semiconductor film;
• and
• adding an impurity to the fourth semiconductor film to form source and drain regions.

A method for manufacturing a semiconductor device, comprising:

• forming a first semiconductor film comprising an amorphous structure on an insulating surface;
• adding a metal element to the first semiconductor film comprising the amorphous structure;
• crystallizing the first semiconductor film to form a second semiconductor film comprising a crystalline structure;
• irradiating the second semiconductor film with laser light;
• forming a third semiconductor film by patterning the second semiconductor film;
• performing a first heat treatment of the third semiconductor film;
• oxidizing a surface of the third semiconductor film by using a solution comprising ozone to form an oxide film after the step of performing the first heat treatment of the third semiconductor film;
• forming a fourth semiconductor film comprising a rare gas element over the oxide film;
• performing a second heat treatment to reduce the metal element in the third semiconductor film by gettering of the metal element into the fourth semiconductor film;
• removing the fourth semiconductor film;
• and
• removing the oxide film.

A method for manufacturing a semiconductor device, comprising:

• forming a first semiconductor film comprising an amorphous structure on an insulating surface;
• adding a metal element to the first semiconductor film comprising the amorphous structure;
• crystallizing the first semiconductor film to form a second semiconductor film comprising a crystalline structure;
• irradiating the second semiconductor film with laser light;
• forming a third semiconductor film by patterning the second semiconductor film;
• oxidizing a surface of the third semiconductor film by using a solution comprising ozone to form an oxide film;
• performing a first heat treatment of the second third semiconductor film after the step of oxidizing the surface of the third semiconductor film;
• forming a fourth semiconductor film including a rare gas element over the oxide film;
• performing a second heat treatment to reduce the metal element in the third semiconductor film by gettering of the metal element into the fourth semiconductor film;
• removing the fourth semiconductor film;
• and
• removing the oxide film.

A method for manufacturing a semiconductor device, comprising:

• forming a first semiconductor film comprising an amorphous structure on an insulating surface;
• adding a metal element to the first semiconductor film comprising the amorphous structure;
• crystallizing the first semiconductor film to form a second semiconductor film including a crystalline structure;
• irradiating the second semiconductor film with laser light;
• performing a first heat treatment of the second semiconductor film after the step of irradiating the second semiconductor film with the laser light;
• oxidizing a surface of the second semiconductor film by using a solution including ozone to form an oxide film after the step of performing the first heat treatment of the second semiconductor film;
• performing a second heat treatment of the second semiconductor film after the step of oxidizing the surface of the second semiconductor film;
• forming a third semiconductor film comprising a rare gas element over the oxide film;
• performing a third heat treatment to reduce the metal element in the second semiconductor film by gettering of the metal element into the third semiconductor film;
• removing the third semiconductor film;
• and
• removing the oxide film.