Device and method for improving crystallization
The invention discloses a method and a device of improving crystallization ratio of polysilicon, which is applied to the process that the amorphous silicon layer converts into the polysilicon layer. More specifically, superposing at least two pulse laser beams into a superposed pulse laser beam. The pulse width of the superposed pulse laser beam is larger than each pulse laser beam. Next, utilizing the superposed pulse laser beam to irradiate onto the amorphous silicon layer for transforming the amorphous silicon layer into polysilicon layer. The superposed pulse laser beam irradiates onto the surface of the amorphous silicon layer. The amorphous silicon layer is transformed into the polysilicon layer. Consequently, the crystallization ratio of polysilicon is improved.
1. A method for improving crystallization ratio of polysilicon, comprising:
providing an amorphous silicon layer covered on a surface of a hard substrate;
superposing at least two pulse laser beams into a superposed pulse laser beam; and
utilizing the superposed pulse laser beam to irradiate onto the amorphous silicon layer for transforming the amorphous silicon layer into polysilicon layer;
wherein a pulse width of the superposed pulse laser beam is bigger than each of that of the each laser beam, and a value of a peak power of the pulse laser beam is lower than a preconfigured value.
2. The method as disclosed in claim 1 , wherein the range of laser intensity of the superposed pulse laser beam is from 250 mJ/cm 2 to 320 mJ/cm 2 .
3. The method as disclosed in claim 1 , wherein the range of pulse width of the superposed pulse laser beam is from 150 ns to 300 ns.
4. The method as disclosed in claim 1 , wherein the pulse interval of the superposed pulse laser beam is from 20 ns to 80 ns.
5. The method as disclosed in claim 1 , wherein each pulse laser beam is generated by one or multiple excimer laser sources.
6. The method as disclosed in claim 1 , wherein the frequency of each of the pulse laser beam is same.
7. The method as disclosed in claim 1 , wherein the phase difference of two adjacent pulse laser beams is smaller than the pulse laser width of the pulse laser beam.
8. The method as disclosed in claim 1 , wherein the wavelength of each of the pulse laser beam is 308 nm.
9. The method as disclosed in claim 1 , wherein the pulse laser beam is xenon chlorine laser.
10. The method as disclosed in claim 1 , wherein one of the two adjacent the pulse laser beams is S polarized light, and the other one is P polarized light.
11. The method as disclosed in claim 10 , wherein the hard substrate is a glass substrate or a plastic substrate.
12. A device for improving crystallization ratio of polysilicon, comprising:
a condenser lens for focusing laser beams irradiated onto it and forming a superposed pulse laser beam to be irradiated onto an upper surface of a amorphous silicon layer;
at least two laser sources for generating the laser beams, each of the laser sources generating a laser beam; and
a plurality of reflectors corresponding to etch laser source for reflecting the laser beam to the condenser lens;
wherein, the condenser lens is located between the reflectors and the amorphous silicon layer, a pulse width of the superposed pulse laser beam is bigger than each of that of the each laser beam, and a value of a peak power of the pulse laser beam is lower than a preconfigured value.
13. The device as disclosed in claim 12 , wherein the wavelength of the laser that each of the laser source generates is 308 nm.
14. The device as disclosed in claim 12 , wherein the laser is xenon chlorine laser.
15. The device as disclosed in claim 12 , wherein the transmitting frequency of the laser source is same.
16. The device as disclosed in claim 12 , wherein one of the two adjacent the pulse laser beams is S polarized light, and the other one is P polarized light.