Crystallization method, crystallization apparatus, processed substrate, thin film transistor and display apparatus

A processed substrate comprising:

• a substrate formed of at least one material of an insulator, a semiconductor and a metal;
• a first insulating layer provided on the substrate;
• an amorphous semiconductor film or a non-single crystal semiconductor film provided on the first insulating layer;
• and
• a second insulating layer which is provided on the amorphous semiconductor film or the non-single-crystal semiconductor film and has a thickness which is not less than 30 nm and not more than 500 nm.

A thin film transistor which is of a top gate type, comprising:

• a semiconductor thin film including source, drain and channel areas formed on an insulating substrate;
• a gate insulating film provided on the semiconductor thin film;
• and a gate electrode provided on a side of the semiconductor thin film through the gate insulating film,
• wherein the semiconductor thin film is crystallized by irradiation of laser beam having a light intensity distribution which cyclically repeats a monotonous increase and a monotonous decrease in an irradiation area and melts a non-single-crystal semiconductor thin film.

A thin film transistor which is of a bottom gate type, comprising:

• a gate electrode formed on an insulating substrate;
• a gate insulating film provided on the gate electrode;
• and a semiconductor thin film which includes source, drain and channel areas and is provided to cover the gate electrode through the gate insulating film,
• wherein the semiconductor thin film is crystallized by irradiation of laser beam having a light intensity distribution which cyclically repeats a monotonous increase and a monotonous decrease in an irradiation area and melts a non-single-crystal semiconductor thin film.

A thin film transistor comprising:

• a source area and a drain area which are provided to sandwich a channel area in a crystallized area of the non-single-crystal semiconductor thin film by the crystallization method according to claim 1, and in which predetermined impurities are doped;
• a gate insulating film formed on the channel area;
• a gate electrode formed on the gate insulating film;
• a source electrode which electrically connects with the source area;
• and
• a drain electrode which electrically connects with the drain area.