Patent ID: 7348631
Filing Date: 2008-03-25
Classification: G02F,H01L

Abstract:
1. A thin film transistor substrate, comprising: a substrate; a first bottom gate electrode formed above the substrate; a first gate insulating film formed above the substrate, the first gate insulating film covering the first bottom gate electrode; a plurality of island-shaped semiconductor films formed above the first gate insulating film, the island-shaped semiconductor films including a first island-shaped semiconductor film which intersects with the first bottom gate electrode; a second gate insulating film formed above the first gate insulating film, the second gate insulating film being thinner than the first gate insulating film and covering the plurality of island-shaped semiconductor films; a first top gate electrode formed above the second gate insulating film, the first top gate electrode intersecting with a second island-shaped semiconductor film of the plurality of island-shaped semiconductor films which does not intersect with the first bottom gate electrode; a first conductive type source/drain region formed on each of the first and second island-shaped semiconductor films, the first conductive type source/drain region being formed on either side of the first or second gate electrode; and a first conductive type LDD region formed on the first island-shaped semiconductor film, the first conductive type LDD region being formed on a portion more inside than the first conductive type source/drain region and partially covering the first bottom gate electrode excluding a channel region which resides above the first bottom gate electrode, the first conductive type LDD region being lower in impurity concentration than the first conductive type source/drain region.