Image Display Device And Method For Manufacturing The Same

Abstract

An image display device manufactured by using a polycrystalline semiconductor film. The polycrystalline semiconductor film is composed of crystal grains with a region free from crystal grain boundaries of at least 2 μm in width and at least 3 μm in length, small crystal grain boundary groups each composed of three or more crystal grain boundaries arranged substantially in parallel to each other and with an interval of not greater than 100 μm are included in a part of the region, and the small crystal grain boundary groups are partially eliminated.

1 . An image display device manufactured by using a polycrystalline semiconductor film, wherein the polycrystalline semiconductor film is composed of crystal grains with a region free from crystal grain boundaries of at least 2 μm in width and at least 3 μm in length, small crystal grain boundary groups each composed of at least three crystal grain boundaries arranged substantially in parallel to each other and with an interval of not greater than 100 μm are included in a part of the region, and the small crystal grain boundary groups are partially eliminated. 
   
   
       2 . An image display device manufactured by using a polycrystalline semiconductor film, wherein the polycrystalline semiconductor film is composed of crystal grains with a region free from crystal grain boundaries of at least 0.2 μm in width and at least 2 μm in length, and in most of points where three crystal grain boundaries cross one another, three angles formed between the adjacent crystal grain boundaries are not smaller than 90°. 
   
   
       3 . An image display device manufactured by using a polycrystalline semiconductor film, wherein the polycrystalline semiconductor film is composed of crystal grains with a region free from crystal grain boundaries of at least 2 μm in width and at least 3 μm in length, and a plurality of protrusions are disposed on the surface of the polycrystalline semiconductor film. 
   
   
       4 . An image display device manufactured by using polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , intervals between adjacent protrusions are not shorter than 0.10 μm and not longer than 0.80 μm. 
   
   
       5 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , a density of the protrusions is not lower than 5 pieces/μm 2  and not higher than 20 pieces/μm 2 . 
   
   
       6 . An image display device manufactured by using a polycrystalline film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , the protrusions are distributed on virtual lines extending in the same direction. 
   
   
       7 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 6 , a distance between the virtual lines is not shorter than 0.10 μm and not longer than 0.80 μm. 
   
   
       8 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , groups of the protrusions formed on crystal grain boundaries and groups of the protrusions formed in the regions where there is no crystal grain boundary are mixed together. 
   
   
       9 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , an average value of a difference in height in the film is not smaller than 2 μm and not larger than 50 μm. 
   
   
       10 . An image display device manufactured by using a polycrystalline semiconductor film, wherein the polycrystalline semiconductor film is composed of crystal grains with a region free from crystal grain boundaries of at least 0.2 μm in width and at least 3 μm in length, and each boundary connecting the points where three crystal grain boundaries cross one another has windings. 
   
   
       11 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 10 , each of the windings is composed of a set of curves having an arc length of not greater than 1 μm and a curvature radius of not greater than 20 μm. 
   
   
       12 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 1 , crystal grains with a crystal orientation of [100] in a direction normal to the film surface are included at an area ratio of at least 20%, crystal grains with a crystal orientation of [111] in a direction normal to the film surface are included at an area ratio of not greater than 10%, and crystal grains with crystal orientations [110], [100] and [111] indirection normal to the film surface are included and a ratio of the area occupied by the crystal grains with each crystal orientation is not greater than 50%. 
   
   
       13 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 2 , crystal grains with crystal orientation of [110] in a direction normal to the film surface are included at an area ratio of at least 20%, crystal grains with a crystal orientation of [100] in a direction normal to the film surface are included at an area ratio of at least 20%, crystal grains with a crystal orientation of [111] in a direction normal to the film surface are included at an area ratio of not greater than 10%, and crystal grains with crystal orientations of [110], [100] and [111] in direction normal to the film surface are included, and a ratio of the area occupied by the crystal grains with each crystal orientation is not greater than 50%. 
   
   
       14 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , crystal grains with a crystal orientation of [110] in a direction normal to the film surface are included at an area ratio of at least 20%, crystal grains with a crystal orientation of [100] in a direction normal to the film surface are included at an area ratio of at least 20%, crystal grains with a crystal orientation of [111] in a direction normal to the film surface are included at an area ratio of not greater than 10%, and crystal grains with crystal orientations of [110], [100] and [111] in direction normal to the film surface are included, and a ratio of the area occupied by the crystal grains with each crystal orientation is not greater than 50%. 
   
   
       15 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 1 , crystal grains with crystal orientations [110], [100] and [111] in direction of the major axis of the polycrystalline semiconductor film are included, the crystal grains with a crystal orientation of [100] in a direction of the major axis are included at an area ratio of at least 30%, and a ratio of the area occupied by the crystal grains with each crystal orientation is not greater than 70%. 
   
   
       16 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 2 , crystal grains with crystal orientations of [110], [100] and [111] in a direction of the major axis are included, crystal grains with a crystal orientation of [100] in a direction of the major axis are included at an area ratio of at least 30%, and a ratio of the area occupied by the crystal grains with each crystal orientation is not greater than 70%. 
   
   
       17 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , crystal grains with crystal orientations of [110], [100] and [111] in direction of the major axis are included, crystal grains with a crystal orientation of [100] in a direction of the major axis are included at an area ratio of at least 30%, and a ratio of the area occupied by the crystal grains with each crystal orientation is not greater than 70%. 
   
   
       18 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 1 , crystal grains with a crystal orientation [110] in a direction of the minor axis of the polycrystalline semiconductor film are included at an area ratio of at least 25% and not greater than 50%, crystal grains with a crystal orientation of [100] in a direction of the minor axis are included at an area ratio of not greater than 30%, and crystal grains with a crystal orientation of [111] in a direction of the minor axis are included at an area ratio of not greater than 30%. 
   
   
       19 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 2 , crystal grains with a crystal orientation [110] in a direction of the minor axis of the polycrystalline semiconductor film are included at an area ratio of at least 25% and not greater than 50%, crystal grains with a crystal orientation of [100] in a direction of the minor axis are included at an area ratio of not greater than 30%, and crystal grains with a crystal orientation of [111] in a direction of the minor axis are included at an area ratio of not greater than 30%. 
   
   
       20 . An image display device manufactured by using a polycrystalline semiconductor film, wherein, in the polycrystalline semiconductor film as set forth in  claim 3 , crystal grains with a crystal orientation [110] in a direction of the minor axis of the polycrystalline semiconductor film are included at an area ratio of at least 25% and not greater than 50%, crystal grains with a crystal orientation of [100] in a direction of the minor axis are included at an area ratio of not greater than 30%, and crystal grains with a crystal orientation of [111] in a direction of the minor axis are included at an area ratio of not greater than 30%. 
   
   
       21 . An image display device, comprising a pixel circuit of an image display portion, a drive circuit for driving the pixel circuit, and an integrated circuit group or processing and converting an external input signal to a signal needed for image display and for transferring the signal to the drive circuit, and the pixel circuit, the drive circuit and the integrated circuit group are disposed on the same insulating substrate wherein:
 each of the circuits is composed of a device including a plurality of thin film transistors having a semiconductor film as an active layer; and   a part of the thin-film transistor active layer to constitute the drive circuit and the integrated circuit group grows crystal grains by scanning of a first energy beam in a direction along the scanning and is turned to polycrystalline, a first crystal grain is composed of a polycrystalline semiconductor film by decreasing defects within the crystal grain by a second high-speed heat treatment, and an other part of the thin-film transistor active layer is composed of a polycrystalline semiconductor film turned to polycrystalline by the second high-speed heat treatment.   
   
   
       22 . An image display device according to  claim 21 , wherein a part of the thin-film transistors to constitute the drive circuit and the integrated circuit group has an electric field effect mobility of at least 300 cm 2 /Vs and is driven at a standard voltage of not greater than 5 V, and an other part of the thin-film transistors has an electric field effect mobility of 1 cm 2 /Vs to 100 cm 2 /Vs and are driven at standard voltage of at least 5V.