Pulse width method for controlling lateral growth in crystallized silicon films
AssigneeSharp Laboratories of America, Inc.
InventorApostolos Voutsas
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Abstract
A method is provided for crystallizing a silicon film in liquid crystal display (LCD) fabrication. The method comprises: forming an amorphous silicon film having a thickness in the range of 100 to 1000 Angstroms (Å); irradiating the silicon film with a laser pulse having a pulse width of 50 nanoseconds (ns) or greater, as measured at the full-width-half-maximum (FWHM), using a beamlet width in the range of 3 to 20 microns; and, in response to irradiating the silicon film, laterally growing crystal grains. In one example, irradiating the silicon film may include irradiating with a pulse having a pulse width in the range between 30 and 300 ns FWHM, and an energy density in the range from 200 to 1300 millijoules per square centimeter (mJ/cm2).
Claims42
In liquid crystal display (LCD) fabrication, a method for crystallizing a silicon film, the method comprising:
- forming an amorphous silicon film;
- irradiating the silicon film with a laser pulse having a pulse width of greater than 50 nanoseconds (ns), as measured at the full-width-half-maximum (FWHM), and a beamlet width in the range of 3 to 20 microns;
- and,
- in response to irradiating the silicon film, laterally growing crystal grains.
A method for crystallizing a silicon film, the method comprising:
- forming an amorphous silicon film;
- irradiating the silicon film with a laser pulse having a pulse width of 30 nanoseconds (ns) or greater, as measured at the full-width-half-maximum (FWHM), and a beamlet width in the range of 3 to 20 microns;
- stepping a distance across the silicon film and repeating the irradiation;
- and,
- in response, laterally growing crystal grains in the stepped direction, by a length that is more than half the stepped distance.
In liquid crystal display (LCD) fabrication, a method for crystallizing a silicon film, the method comprising:
- forming an amorphous silicon film;
- irradiating the silicon film with a laser pulse having a first energy density sufficient to melt, but not evaporate the silicon film;
- extending the laser pulse at the first energy density to prolong the melt duration of the silicon film;
- and,
- wherein extending the laser pulse at the first energy density to prolong the melt duration of the silicon film includes forming a pulse having a pulse width of greater than 50 nanoseconds (ns), as measured at full-width-half-maximum (FWHM), and a beamlet width in the range of 3 to 20 microns.
In liquid crystal display (LCD) fabrication, a method for crystallizing a silicon film, the method comprising:
- forming an amorphous silicon film overlying a substrate;
- forming a laser pulse having a pulse width of 30 nanoseconds (ns) or greater, as measured at full-width-half-maximum (FWHM), and a beamlet width in the range of 3 to 20 microns;
- irradiating the silicon film with a laser pulse having a first energy density;
- dissipating energy from the silicon film into the substrate;
- maintaining a minimum power into the silicon film;
- and,
- laterally growing crystal grains.
A method for crystallizing a silicon film, the method comprising:
- forming an amorphous silicon film;
- irradiating the silicon film with a laser pulse having a pulse width of 30 nanoseconds (ns) or greater, as measured at the full-width-half-maximum (FWHM), and a beamlet width in the range of 3 to 20 microns;
- stepping a distance across the silicon film and repeating the irradiation;
- and,
- in response, laterally growing crystal grains in the stepped direction.
Dependencies are inferred from the claim text.