Method of annealing a semiconductor
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHongyong Zhang, Naoto Kusumoto
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Abstract
A process for crystallizing an amorphous semiconductor by irradiating a laser beam thereto, which comprises thermally annealing the amorphous semiconductor prior to the crystallization thereof in vacuum or in an inactive gas atmosphere at a temperature not higher than the crystallization temperature of the amorphous semiconductor, and then irradiating a laser beam to the thermally annealed amorphous semiconductor in vacuum or in an inactive gas atmosphere to crystallize the amorphous semiconductor. The process provides a uniform polycrystalline silicon film having high crystallinity, which has less dependence on the energy density of the laser beam which is irradiated thereto for crystallization, and hence useful for thin film devices such as insulated gate field effect transistors.
Claims13
A method for forming a crystalline semiconductor comprising the steps of:
- forming an amorphous semiconductor:
- heat treating said amorphous semiconductor at a temperature not higher than a crystallization temperature of said amorphous semiconductor in order to discharge hydrogen contained in said amorphous semiconductor;
- and then
- irradiating said amorphous semiconductor with a laser after heat treating said amorphous semiconductor to crystallize said amorphous semiconductor.
A method for forming a crystalline semiconductor comprising the steps of:
- thermally annealing an amorphous semiconductor in vacuum or inactive atmosphere in a first chamber at a temperature not higher than a crystallization temperature of said amorphous semiconductor in order to discharge hydrogen contained in said amorphous semiconductor;
- transferring said amorphous semiconductor from said first chamber to a second chamber connected to said first chamber without exposing said amorphous semiconductor to an air;
- and then
- irradiating said amorphous semiconductor with a laser in vacuum or inactive atmosphere in said second chamber to crystallize said amorphous semiconductor.
A method for forming a crystalline semiconductor comprising the steps of:
- forming an amorphous semiconductor;
- heat treating said amorphous semiconductor at a temperature not higher than a crystalline temperature of said amorphous semiconductor in order to discharge hydrogen contained in said amorphous semiconductor;
- and then
- crystallizing said amorphous semiconductor after heat treating.
A method for forming a crystalline semiconductor comprising the steps of:
- forming an amorphous semiconductor;
- heat treating said amorphous semiconductor in order to form dangling bonds in said amorphous semiconductor at a sufficiently low temperature not to initiate a crystallization of said film;
- and then
- crystallizing said amorphous semiconductor after heat.
Dependencies are inferred from the claim text.