Laser irradiation induced surface planarization of polycrystalline silicon films
AssigneeThe Trustees of Columbia University in the City of New York
InventorsJames S. IM, Miao YU
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Abstract
A method for planarizing excimer laser annealed (ELA) poly-crystalline thing films via irradiation. The method includes providing an ELA thin film having an oxide and a top surface with a first surface roughness defined at least by a first plurality of protrusions. The ELA thin film is etched to substantially remove the oxide. At least a portion of the etched ELA thin film is then irradiated using a short-pulse duration excimer laser beam, to form an irradiated thin film with a second surface roughness defined at least by a second plurality of protrusions. The second surface roughness is lower than the first surface roughness.
Claims21
A method, comprising:
- providing a film comprising:
- a polycrystalline thin film having a top surface having a first surface roughness defined by a first plurality of protrusions;
- and
- an oxide layer over the top surface of the thin film;
- etching the film to substantially remove the oxide layer;
- and
- irradiating a portion of the etched film using a short-pulse duration laser beam with controlled energy density to cause partial melting to the portion of the etched film, to form an irradiated polycrystalline thin film having a second surface roughness defined by a second plurality of protrusions wherein the second surface roughness is lower than the first surface roughness.
A method, comprising:
- providing a film comprising:
- a polycrystalline thin film having a top surface having a first surface roughness defined by a first plurality of protrusions;
- and
- an oxide layer over the top surface of the thin film;
- etching the film to substantially remove the oxide layer;
- irradiating a portion of the film using a short-pulse duration laser beam with controlled energy density to cause partial melting to the portion of the etched film form a self-leveling molten layer;
- cooling the self-leveling molten layer;
- and
- forming a modified thin film having a second surface roughness defined by a second plurality of protrusions wherein the second surface roughness is lower than the first surface roughness.
A system for processing a film, the system comprising:
- a laser source configured to supply a sequence of laser pulses;
- laser optics that shape the laser beam into a line beam, the line beam having a fluence that is sufficient to melt at least a partial thickness of the film in an irradiated region, the film comprising a polycrystalline thin film having a top surface having a first surface roughness defined by a first plurality of protrusions and an oxide layer over the top surface of the thin film;
- a stage for supporting the film and configured to translate in at least one direction;
- a processor operably coupled to the laser source;
- and
- a memory operably coupled to the processor and storing a set of processor-issuable instructions that cause the processor to:
- define a region of the film to be planarized;
- etch the film to substantially remove the oxide layer;
- and
- irradiate at least a portion of the etched film using a short-pulse duration laser beam with controlled energy density to cause partial melting to the portion of the etched film, to form an irradiated polycrystalline thin film having a second surface
- roughness defined by a second plurality of protrusions wherein the second surface roughness is lower than the first surface roughness.
Dependencies are inferred from the claim text.