Laser anneal method of a semiconductor layer

A semiconductor layer laser annealling method for obtaining a polycrystal semiconductor layer by irradiating a laser beam on an amorphous semiconductor layer formed on a substrate, wherein

• an energy level in a region to be irradiated by the laser beam is set such that a level towards the rear of a region along which the laser beam scans is lower than that at the front area or the center area of the region.

A semiconductor layer laser annealling method for obtaining a polycrystal semiconductor layer by irradiation of an amorphous semiconductor layer formed on a substrate with a laser beam, wherein

• an energy level in a region to be irradiated by the laser beam is set such that the peak level in the rear area of a region along a scan direction of the laser beam is lower than the upper limit energy level which maximizes semiconductor layer grain size.

A transistor device in which a polycrystal semiconductor layer is formed by subjecting an amorphous semiconductor layer formed on a substrate to laser anneal processing, wherein

• an energy level in a region to be irradiated by a laser beam of the amorphous semiconductor layer is set such that the level in a rear area of a region along a scan direction of the laser beam is lower than the upper limit energy level which maximizes a grain size of the semiconductor layer, and
• the amorphous semiconductor layer is annealed by the laser beam and the polycrystal semiconductor layer obtained is used as an active layer of the transistor device.