(12) United States Patent ao) Patent No.: Us 7,056,382 B2
Chung (45) Date of Patent: Jun. 6,2006
6,322,625 Bl 11/2001 Im
6,392,810 Bl * 5/2002 Tanaka 359/622
6,558,991 Bl * 5/2003 Yamazaki et al 438/151
FOREIGN PATENT DOCUMENTS
Moshe Nazarathy &D.W. Dolfi, "Spread-spectrum nonlinear-optical interactons: quasi-phase matching with pseudorandom polarity reversals", Optics Letters, vol. 12, p. 823, Oct. 1987, pp. 823-825.
Martin M. Fejer, et al., "Quasi-Phase-Matched Second Harmonic Generation: Tuning and Tolerances", IEEE Journal of Quantum Electronics, vol. 28, No. 11, Nov. 1992, pp. 2631-2654.
* cited by examiner
Primary Examiner—Felisa Hiteshew
(74) Attorney, Agent, or Firm—McKenna Long & Aldridge
A method of crystallizing an amorphous silicon layer includes the steps of generating an excimer laser beam having a first energy density and a second energy density, irradiating an amorphous silicon layer with at least one exposure of the excimer, wherein the first energy density melts the amorphous silicon layer to a first depth from a surface of the amorphous silicon layer equal to the first thickness and the second energy density melts the amorphous silicon layer to a second depth from the surface of the amorphous silicon layer less than the first thickness.
5 Claims, 6 Drawing Sheets