Laser-irradiation method and laser-irradiation device

A laser-irradiation method which comprises a process for fabricating a semiconductor device, comprising:

• a first step of forming a thin film amorphous semiconductor on a substrate having an insulating surface;
• a second step of modifying the thin film amorphous semiconductor into a crystalline thin film semiconductor by irradiating a linear light from a pulse-emitting laser and/or by applying a heat treatment;
• a third step of implanting an impurity element which imparts a one conductive type to the crystalline thin film semiconductor;
• and
• a fourth step of activating the impurity element by irradiating a laser light and/or by applying a heat treatment;
• wherein a peak value, a peak width at half height, and a threshold width of a laser energy of the laser light in the second and the fourth steps above are each distributed within a range of approximately ±3% of a standard value.

A laser-irradiation device for irradiating a laser light to a thin film semiconductor provided on a substrate having an insulating surface, comprising:

• means for emitting the laser light;
• a gas processor connected to the means for emitting the laser light;
• a control unit for controlling an output of the laser light by detecting a part of the light emitted from laser and then feeding back the detected result to the means for emitting the laser light;
• optical system means which shape the laser light into a linear beam;
• and
• means for heating the thin film semiconductor;
• wherein, a peak value, a peak width at half height, and a threshold width of a laser energy of the laser light are each distributed within a range of approximately ±3% of a standard value.

A laser-irradiation device for irradiating a laser light to a thin film semiconductor provided on a substrate having an insulating surface, comprising:

• means for emitting the laser light;
• a gas processor connected to the means for emitting the laser light;
• a control unit for controlling an output of the laser by detecting a part of the emitted light and then feeding back the detected result to the means for emitting the laser light;
• optical system means for shaping the laser light into a linear beam;
• means for heating the thin film'semiconductor;
• and
• an auxiliary heating device provided in addition to the means for heating the thin film semiconductor,
• wherein, a peak value, a peak width at half height, and a threshold width of a laser energy of the laser light are each distributed within a range of approximately ±3% of a standard value.