Semiconductor device and method for producing the same

A thin film transistor comprising:

• an insulating film comprising silicon oxide;
• a semiconductor island formed on said insulating film, said semiconductor island including source and drain regions therein and a channel region therebetween;
• a gate insulating film formed over the semiconductor island, said gate insulating film including silicon oxide;
• a gate electrode formed on the gate insulating film, said gate electrode including a metal nitride film formed on the gate insulating film and a metal film formed on the metal nitride film,
• wherein the metal nitride film extends beyond edges of the semiconductor island.

A thin film transistor comprising:

• a semiconductor island formed on an insulating surface, said semiconductor island including source and drain regions therein and a channel region therebetween;
• a gate insulating film formed over the semiconductor island;
• a gate electrode formed over the channel region with the gate insulating film interposed therebetween, said gate electrode including a metal nitride film formed on the gate insulating film and a metal film formed on the metal nitride film,
• wherein the gate electrode extends beyond edges of the semiconductor island and said metal nitride film extends beyond side edges of the metal film in a direction along said source and drain regions.

A thin film transistor comprising:

• an insulating film comprising silicon oxide;
• a semiconductor island formed on said insulating film, said semiconductor island including source and drain regions therein and a channel region therebetween;
• a gate insulating film formed over the semiconductor island;
• a gate electrode formed over the channel region with the gate insulating film interposed therebetween, said gate electrode including a metal nitride film formed on the gate insulating film and a metal film formed on the metal nitride film,
• wherein the gate electrode extends beyond edges of the semiconductor island and said metal nitride film extends beyond side edges of the metal film in a direction along said source and drain regions.

A thin film transistor comprising:

• a semiconductor island formed on an insulating surface, said semiconductor island including source and drain regions therein and a channel region therebetween;
• a gate insulating film formed over the semiconductor island;
• a gate electrode formed over the channel region with the gate insulating film interposed therebetween, said gate electrode including a titanium nitride film formed on the gate insulating film and an aluminum film formed on the titanium nitride film,
• wherein the gate electrode extends beyond edges of the semiconductor island and said titanium nitride film extends beyond side edges of the aluminum film in a direction along said source and drain regions.

A thin film transistor comprising:

• an insulating film comprising silicon oxide;
• a semiconductor island formed on said insulating film, said semiconductor island including source and drain regions therein and a channel region therebetween;
• a gate insulating film formed over the semiconductor island;
• a gate electrode formed over the channel region with the gate insulating film interposed therebetween, said gate electrode including a metal nitride film formed on the gate insulating film and a metal film formed on the metal nitride film,
• wherein the metal nitride film extends beyond edges of the semiconductor island and said metal nitride film extends beyond side edges of the metal film in a direction along said source and drain regions.