NOVELTY - The method (100) comprises: identifying a first treatment zone; forming a molten area of the first treatment zone by exposing a surface of the first treatment zone to first laser pulses and to second laser pulses, where the first laser pulses have a non-uniformity of less than 5%; recrystallizing (108) the molten area of the first treatment zone while exposing the first treatment zone to third laser pulses; identifying a second treatment zone; and repeating the forming and recrystallizing steps. The first laser pulses and the second laser pulses have the same duration and intensity.    USE - The method is useful for treating a substrate (claimed) to form a polycrystalline or monocrystalline semiconductor layer on the substrate that is useful for forming solar cells, three dimensional memory devices, and photonic devices such as LED.    ADVANTAGE - The method is capable of efficiently, rapidly, and economically forming the polycrystalline or monocrystalline semiconductor layer on the substrate.    DETAILED DESCRIPTION - The method (100) comprises: identifying a first treatment zone; forming a molten area of the first treatment zone by exposing a surface of the first treatment zone to first laser pulses and to second laser pulses, where the first laser pulses have a non-uniformity of less than 5%; recrystallizing (108) the molten area of the first treatment zone while exposing the first treatment zone to third laser pulses; identifying a second treatment zone; and repeating the forming and recrystallizing steps. Duration between the first laser pulses and the second laser pulses is less than a time necessary for a portion of the molten area to refreeze. The first laser pulses and the second laser pulses have the same duration and intensity. Each pulse of the third laser pulses has the same duration and intensity as the first laser pulses, or duration or an intensity that is different from the first laser pulses. The second treatment zone and the first treatment zone share a boundary. Duration between each pulse of the third laser pulses is more than a time to freeze the portion of the first treatment zone. Each pulse of the third laser pulses melts a portion of a recrystallized area. The second treatment zone is adjacent to the first treatment zone. Power delivered by the second laser pulses is higher than a power delivered by the first laser pulses. Power delivered by the third laser pulses is less than a power delivered by the first laser pulses and a power delivered by the second laser pulses. The first pulses are one pulse, and the second pulses comprise multiple pulses that overlap in time. The pulses laser pulses have an overlap factor of 10-40%. Each pulse of the first laser pulses has a duration of 20-30 nseconds and a power of 107-109 W/cm2.    DESCRIPTION OF DRAWING(S) - The figure shows a flow diagram of a method for treating a substrate.    Method for treating substrate (100)    Forming an amorphous semiconductor layer on substrate (102)    Directing pulses of electromagnetic energy toward the layer (104)    Progressively melting a portion of the layer (106)    Recrystallizing the molten area. (108)