THIN-FILM TRANSISTOR AND ITS MANUFACTURE

PURPOSE: To increase a channel length by forming a thin film transistor channel to bend along a trench surface. CONSTITUTION: A trench 11 is formed in a first insulation film 1 and a silicon nitride film 2 is deposited in a surface of the first insulation film 1. After a second insulation film 3 is deposited in an upper surface thereof, a photosensitive film 12 is applied to an upper part thereof and etched back for forming a pattern of the second insulation film 3 leaving the second insulation film 3 on a bottom part and a side surface of the trench 11. After the photosensitive film 12 is removed and a silicon layer 4 for thin film transistor channel is deposited all over, the silicon layer 4 for a channel is formed leaving a part wherein a channel, a source and a drain are formed. Then, a tunnel 13 of a small width is formed in a trench upper surface. After the thin film transistor gate insulation film 5 is formed, a silicon layer 6 for a gate is deposited in a surface of the gate insulation film 5 which is in an inside of a tunnel and an upper part of the silicon layer 4 for a channel. After a gate 6A is formed, a channel 7 is formed of the silicon layer 4 for a channel wherein impurities are not injected.