Patent ID: 7638846
Filing Date: 2009-12-29
Classification: G02F,H01L

Abstract:
1. A semiconductor device comprising: at least a first n-channel thin film transistor being formed in a display region over a substrate; and at least a second n-channel thin film transistor and at least a p-channel thin film transistor in a drive circuit each being formed in a periphery of the display region over the substrate; each of the second n-channel thin film transistor and the p-channel thin film transistor includes: a gate electrode formed over the substrate, a first insulating film formed over the gate electrode, a second insulating film comprising silicon oxide formed over the first insulating film, a crystalline semiconductor film formed over the second insulating film, wherein a channel length of the p-channel thin film transistor is shorter than that of the second n-channel thin film transistor, wherein the first n-channel thin film transistor has at least first and second channel regions, wherein the crystalline semiconductor film of the second n-channel thin film transistor comprises a pair of LDD regions located between a channel region and source and drain regions respectively, wherein at least a portion of the source and drain regions of the p-channel thin film transistor is formed so as to overlap with the gate electrode of the p-channel thin film transistor, wherein at least a portion of the LDD region of the second n-channel thin film transistor is formed so as to overlap with the gate electrode of the second n-channel thin film transistor, wherein source and drain regions of the second n-channel thin film transistor is not formed so as to overlap with the gate electrode of the second n-channel thin film transistor.