Thin film transistor having crystalline semiconductor layer obtained by irradiation

A thin film semiconductor integrated circuit comprising:

• at least two thin film transistors formed on an insulating surface, said at least two thin film transistors being formed from a semiconductor film formed on an insulating surface;
• and
• a marker for aligning a mask, comprising the same material as said semiconductor film and provided separately from said semiconductor film and on said insulating surface,
• wherein at least a part of said semiconductor film of said at least two thin film transistors is thinner than said marker.

A thin film transistor comprising:

• a thin film semiconductor layer formed on an insulating surface;
• gate electrodes formed thereon, and
• a marker for aligning a mask, comprising the same material as said semiconductor layer and provided separately from said semiconductor layer and on said insulating surface,
• wherein at least a part of said semiconductor layer is thinner than said marker.

A thin film semiconductor device comprising:

• an active layer of thin film semiconductor which is present on an insulating surface;
• a gate insulating film having a thickness of 500.ANG. or less, and
• a marker for aligning a mask, comprising the same semiconductor with said active layer and provided separately from said active layer and on said insulating surface,
• wherein said semiconductor is thinner in at least a part of said active layer than in said marker.

A thin film semiconductor device comprising:

• a thin film semiconductor layer formed on an insulating surface, and
• a marker for aligning a mask, comprising the same material as said semiconductor layer and provided separately from said semiconductor layer and on said insulating surface,
• wherein at least a part of said semiconductor layer is thinner than said marker, and
• wherein the average thickness of a region of the semiconductor layer having a gate electrode formed thereon is substantially the same as the average thickness of a part of the periphery of said semiconductor layer.

A thin film semiconductor device comprising:

• an active layer of thin film semiconductor which is present on an insulating surface and has a thickness of 300.ANG. or less;
• a gate insulating film which has a thickness of 200.ANG. to 1500.ANG. and is formed by non-thermal oxidation, and
• a marker for aligning a mask, comprising the same semiconductor with said active layer and provided separately from said active layer and on said insulating surface, said marker having a thickness of 400.ANG. to 1500.ANG.,
• wherein said semiconductor is thinner in at least a part of said active layer than in said marker.

A thin film semiconductor device comprising:

• a thin film semiconductor layer which is present on an insulating surface and comprises a channel;
• a gate insulating film and a gate electrode on the semiconductor layer, and
• a marker for aligning a mask, comprising the same material as said semiconductor layer and provided separately from said semiconductor layer and on said insulating surface,
• wherein a part of said thin film semiconductor layer is thinner than said marker, said part of said semiconductor layer containing said channel and extending beyond said channel.