Method of manufacturing an active matrix substrate and an image display device using the same
The present invention provides a manufacturing method of a high performance active matrix substrate at a high throughput with a less expensive apparatus, and an image display device using the active matrix substrate. On a stage moving in the short axis direction X and long axis direction Y on a rail, a glass substrate is carried, which has an amorphous silicon semiconductor film formed. Polycrystallized and large grain silicon film may be obtained by intensity modulating the pulsed laser beam in a line beam shape by means of a phase shift mask with a periodicity in the long axis direction Y of the laser beam, moving the laser beam randomly in the modulation direction of the amorphous silicon semiconductor film formed on the glass substrate to expose to crystallize the film. The image display device may incorporate an active matrix substrate having active elements such as thin film transistors formed by this silicon film.
1. An image display device including an active matrix substrate made of a dielectric substrate having a pixel circuit with a matrix array of a number of pixels and a pixel driver circuit located outward from said pixel area, said active matrix substrate comprising:
a polycrystalline semiconductor film deposited on said dielectric substrate,
wherein a plurality of linear arrays of hillocks are located on a surface of the polycrystalline semiconductor film in a direction parallel to each other, and
intervals between the linear arrays are random.
2. An image display device set forth in claim 1 , further comprising:
a thin film transistor using said polycrystalline semiconductor film for a channel thereof.
3. An image display device set forth in claim 2 , further comprising:
a plurality of mutually intersecting wirings formed on said dielectric substrate;
a pixel formed in the vicinity of said intersection of wirings to vary the transmittance or reflectance or amount of light emission; and
a thin film transistor formed in said pixel for serving as a switch for selecting said pixel,
wherein said thin film transistor is formed with a channel using said polycrystalline semiconductor film.
4. An image display device set forth in claim 2 , further comprising:
a plurality of mutually intersecting wirings on said dielectric substrate;
a pixel formed in the vicinity of said intersection of wirings;
a light emitting element having an organic film formed within said pixel;
a thin film transistor formed within said pixel for driving said light emitting element;
wherein a channel direction of said thin film transistor is parallel to a periodic direction of the hillocks of said polycrystalline semiconductor film and a length of a channel of said thin film transistor is a multiple of a natural number of the periodicity of the hillocks of said polycrystalline semiconductor film.