Display device comprising an antioxidant film formed on a microcrystalline semiconductor film wherein the antioxidant film has a recessed portion overlapping a channel region

A display device comprising:

• a thin film transistor comprising:
• a gate electrode;
• a gate insulating film formed over the gate electrode;
• a microcrystalline semiconductor film formed over the gate insulating film, the microcrystalline semiconductor film comprising a channel formation region;
• an amorphous semiconductor film formed on the microcrystalline semiconductor film, the amorphous semiconductor film comprising an end portion and a recessed portion overlapping the channel formation region;
• a pair of semiconductor films formed over the amorphous semiconductor film, the pair of semiconductor films including an impurity element imparting one conductivity type;
• and
• a source electrode and a drain electrode formed over the pair of semiconductor films,
• wherein edges of the source electrode and the drain electrode are aligned with edges of the pair of semiconductor films,
• wherein an edge of the amorphous semiconductor film is aligned with an edge of the microcrystalline semiconductor film,
• wherein the source electrode and the drain electrode do not overlap with a horizontal upper surface of the end portion of the amorphous semiconductor film,
• wherein the microcrystalline semiconductor film has crystal grains with a diameter of 0.5 nm to 20 nm inclusive in an amorphous semiconductor,
• wherein a thickness of the microcrystalline semiconductor film is 1 nm to 300 nm inclusive,
• wherein a thickness of the amorphous semiconductor film is 1 nm to 100 nm inclusive, and
• wherein the amorphous semiconductor film includes silicon and nitrogen.

A display device comprising:

• a thin film transistor comprising:
• a gate electrode;
• a gate insulating film formed over the gate electrode;
• a microcrystalline semiconductor film formed over the gate insulating film, the microcrystalline semiconductor film comprising a channel formation region;
• an antioxidant film formed on the microcrystalline semiconductor film, the antioxidant film comprising an end portion and a recessed portion overlapping the channel formation region;
• a pair of semiconductor films formed over the antioxidant film, the pair of semiconductor films including an impurity element imparting one conductivity type;
• and
• a source electrode and a drain electrode formed over the pair of semiconductor films,
• wherein edges of the source electrode and the drain electrode are aligned with edges of the pair of semiconductor films,
• wherein an edge of the antioxidant film is aligned with an edge of the microcrystalline semiconductor film,
• wherein the source electrode and the drain electrode do not overlap with a horizontal upper surface of the end portion of the antioxidant film, and
• wherein the antioxidant film includes silicon and nitrogen.

A display device comprising:

• a thin film transistor comprising:
• a gate electrode;
• a gate insulating film formed over the gate electrode;
• a microcrystalline semiconductor film formed over the gate insulating film, the microcrystalline semiconductor film comprising a channel formation region;
• an amorphous semiconductor film formed on the microcrystalline semiconductor film, the amorphous semiconductor film comprising an end portion and a recessed portion overlapping the channel formation region;
• a pair of semiconductor films formed over the amorphous semiconductor film, the pair of semiconductor films including an impurity element imparting one conductivity type;
• and
• a source electrode and a drain electrode formed over the pair of semiconductor films,
• wherein edges of the source electrode and the drain electrode are aligned with edges of the pair of semiconductor films,
• wherein an edge of the amorphous semiconductor film is aligned with an edge of the microcrystalline semiconductor film,
• wherein the source electrode and the drain electrode do not overlap with a horizontal upper surface of the end portion of the amorphous semiconductor film, and
• wherein the amorphous semiconductor film includes silicon and nitrogen.