Patent ID: 7297982

Claim:
A display device comprising a pixel region having a plurality of pixels and a peripheral circuit region disposed adjacent to said pixel region including circuits coupled to said plurality of pixels, wherein said peripheral circuit region includes polycrystalline thin film transistors comprised of polycrystalline semiconductor and having a semiconductor crystalline grain of a first kind in a channel region thereof; wherein a grain size of said semiconductor crystalline grain of said first kind in a channel region of one of said polycrystalline thin film transistors is large enough to extend into both source and drain regions disposed on opposite sides of said channel region of said one of said polycrystalline thin film transistors, wherein a respective one of said polycrystalline thin film transistors is fabricated in an island form, and a channel region of said respective one of said polycrystalline thin film transistors includes at least one crystal grain having a crystal grain boundary, in a top surface of said channel region, in a direction of a line connecting a drain region and a source region of said respective one of said polycrystalline thin film transistors, and wherein a grain size of semiconductor crystalline grains in said channel regions of said polycrystalline thin film transistors in said peripheral circuit region is at least 3 μm, and a grain size of semiconductor crystalline grains in channel regions of polycrystalline thin film transistors in said pixel region is in a range of from 0.05 μm to 0.3 μm.