TRANSISTOR
According to one embodiment, a transistor includes a first gate electrode, a second gate electrode, an oxide semiconductor layer disposed between the first gate electrode and the second gate electrode, and a source electrode and a drain electrode each connected to the oxide semiconductor layer, wherein the oxide semiconductor layer includes a channel forming region, a source region, and a drain region, a light irradiation region which is made low-resistance by irradiating light thereto is each formed between the channel forming region and the source region and between the channel forming region and the drain region, and the first date electrode and the second gate electrode have different lengths.
1 . A transistor comprising:
a first gate electrode;
a second gate electrode opposed to the first gate electrode;
an oxide semiconductor layer disposed between the first gate electrode and the second gate electrode; and
a source electrode and a drain electrode each connected to the oxide semiconductor layer, wherein the oxide semiconductor layer includes a channel forming region, a source region, and a drain region,
a light irradiation region which is made low-resistance by irradiating light thereto is each formed between the channel forming region and the source region and between the channel forming region and the drain region, and
the first date electrode and the second gate electrode have different lengths.
2 . The transistor according to claim 1 , wherein
the source region and the drain region each include an impurity element, and
the second gate electrode is longer than the first gate electrode.
3 . The transistor according to claim 2 , wherein the impurity element is hydrogen, argon, phosphorous, or boron.
4 . The transistor according to claim 1 , wherein the source electrode and the drain electrode contact the oxide semiconductor layer, and
the second gate electrode is longer than the first gate electrode.
5 . The transistor according to claim 1 , wherein
the source region and the drain region each include an impurity element, and
the first gate electrode is longer than the second gate electrode.
6 . The transistor according to claim 1 , wherein
the source electrode and the drain electrode contact the oxide semiconductor layer, and
the first gate electrode is longer than the second gate electrode.
7 . The transistor according to claim 1 , further comprising an insulating layer between the oxide semiconductor layer and the second gate electrode, wherein
the insulating layer includes a first layer contacting the channel forming region and a second layer contacting the light irradiation region, and
defects included in the first layer are less than defects included in the second layer.
8 . The transistor according to claim 1 , wherein the light has luminosity of 100 cd/m 2 or more.