Semiconductor device and method for fabricating the same

A semiconductor device comprising an n-channel thin-film transistor and a p-channel thin-film transistor,

• wherein the n-channel thin-film transistor and the p-channel thin-film transistor each include:
• a semiconductor layer, in which a crystalline region, including a channel forming region, a source region and a drain region, is defined;
• a gate electrode for controlling the conductivity of the channel forming region;
• and
• a gate insulating film, which is provided between the gate electrode and the semiconductor layer, and
• wherein the semiconductor layer includes a gettering region outside of the crystalline region thereof.

A method for fabricating a semiconductor device, the method comprising the steps of:

• preparing an amorphous semiconductor film, to at least part of which a catalytic element, promoting crystallization, has been added;
• subjecting the amorphous semiconductor film to a first annealing process, thereby crystallizing at least a portion of the amorphous semiconductor film and obtaining a semiconductor film including a crystalline region;
• patterning the semiconductor film into a plurality of island-shaped semiconductor layers, each including the crystalline region;
• selectively adding a gettering element to a portion of each said island-shaped semiconductor layer other than portions to be source and drain regions, thereby defining an amorphized gettering region;
• and
• subjecting the island-shaped semiconductor layers to a second annealing process, thereby diffusing at least part of the catalytic element toward the gettering region in each said island-shaped semiconductor layer.

A method for fabricating a semiconductor device, the method comprising the steps of:

• preparing an amorphous semiconductor film, to at least part of which a catalytic element, promoting crystallization, has been added;
• subjecting the amorphous semiconductor film to a first annealing process, thereby crystallizing at least a portion of the amorphous semiconductor film and obtaining a semiconductor film including a crystalline region;
• patterning the semiconductor film into a plurality of island-shaped semiconductor layers, each including the crystalline region;
• forming a gate insulating film over each said island-shaped semiconductor layer;
• forming a gate electrode on the gate insulating film;
• introducing a dopant into a selected portion of the island-shaped semiconductor layer, thereby forming an amorphized gettering region in a portion of the island-shaped semiconductor layer other than portions to be source and drain regions;
• and
• subjecting the island-shaped semiconductor layers to a second annealing process, thereby diffusing at least part of the catalytic element toward the gettering region in each said island-shaped semiconductor layer.

A method for fabricating a semiconductor device, the method comprising the steps of:

• preparing an amorphous semiconductor film, to at least part of which a catalytic element, promoting crystallization, has been added;
• subjecting the amorphous semiconductor film to a first annealing process, thereby crystallizing at least a portion of the amorphous semiconductor film and obtaining a semiconductor film including a crystalline region;
• patterning the semiconductor film into a first island-shaped semiconductor layer and a second island-shaped semiconductor layer, each including the crystalline region;
• forming a gate insulating film over each said island-shaped semiconductor layer;
• forming a first gate electrode on the gate insulating film on the first island-shaped semiconductor layer, on which an n-channel thin-film transistor will be formed, and a second gate electrode on the gate insulating film on the second island-shaped semiconductor layer, on which a p-channel thin-film transistor will be formed, respectively;
• introducing an n-type dopant element into the first and second island-shaped semiconductor layers with the first and second gate electrodes used as a mask, thereby forming a source region, a drain region and a gettering region for the n-channel thin-film transistor and a gettering region for the p-channel thin-film transistor;
• forming a first mask, which exposes a portion of the first island-shaped semiconductor layer of the n-channel thin-film transistor, over the first gate electrode, and a second mask, which defines a third gate electrode for the p-channel thin-film transistor, on the second gate electrode, respectively;
• patterning the second gate electrode into the third gate electrode by using the second mask;
• introducing a p-type dopant element into portions of the first and second island-shaped semiconductor layers, which are not covered with the first mask or the third gate electrode, thereby forming an amorphized gettering region for the n-channel thin-film transistor and the source region, drain region and amorphized gettering region for the p-channel thin-film transistor, respectively;
• and
• conducting a second annealing process such that at least part of the catalytic element in the first and second island-shaped semiconductor layers is introduced into the gettering regions that have been amorphized by being doped with both the p-type dopant element and the n-type dopant element.

A method for fabricating a semiconductor device, the method comprising the steps of:

• preparing an amorphous semiconductor film, to at least part of which a catalytic element, promoting crystallization, has been added;
• subjecting the amorphous semiconductor film to a first annealing process, thereby crystallizing at least a portion of the amorphous semiconductor film and obtaining a semiconductor film including a crystalline region;
• patterning the semiconductor film into a first island-shaped semiconductor layer and a second island-shaped semiconductor layer, each including the crystalline region;
• forming a gate insulating film over each said island-shaped semiconductor layer;
• forming a first gate electrode on the gate insulating film on the first island-shaped semiconductor layer, on which a p-channel thin-film transistor will be formed, and a second gate electrode on the gate insulating film on the second island-shaped semiconductor layer, on which an n-channel thin-film transistor will be formed, respectively;
• introducing a p-type dopant element into the first and second island-shaped semiconductor layers with the first and second gate electrodes used as a mask, thereby forming a source region, a drain region and a gettering region for the p-channel thin-film transistor and a gettering region for the n-channel thin-film transistor;
• forming a first mask, which exposes a portion of the first island-shaped semiconductor layer of the p-channel thin-film transistor, over the first gate electrode, and a second mask, which defines a third gate electrode for the n-channel thin-film transistor, on the second gate electrode, respectively;
• patterning the second gate electrode into the third gate electrode by using the second mask;
• introducing an n-type dopant element into portions of the first and second island-shaped semiconductor layers, which are not covered with the first mask or the third gate electrode, thereby forming an amorphized gettering region for the p-channel thin-film transistor and the source region, drain region and amorphized gettering region for the n-channel thin-film transistor, respectively;
• and
• conducting a second annealing process such that at least part of the catalytic element in the first and second island-shaped semiconductor layers is introduced into the gettering regions that have been amorphized by being doped with both the n-type dopant element and the p-type dopant element.