SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME
A semiconductor device having a reduced amount of oxygen vacancy in a channel formation region of an oxide semiconductor is provided. Further, a semiconductor device which includes an oxide semiconductor and has improved electric characteristics is provided. Furthermore, a methods for manufacturing the semiconductor device is provided. An oxide semiconductor film is formed; a conductive film is formed over the oxide semiconductor film at the same time as forming a low-resistance region between the oxide semiconductor film and the conductive film; the conductive film is processed to form a source electrode and a drain electrode; and oxygen is added to the low-resistance region between the source electrode and the drain electrode, so that a channel formation region having a higher resistance than the low-resistance region is formed and a first low-resistance region and a second low-resistance region between which the channel formation region is positioned are formed.
1 . A semiconductor device comprising:
a first metal oxide layer;
an oxide semiconductor layer over the first metal oxide layer;
a second metal oxide layer over the oxide semiconductor layer;
a source electrode and a drain electrode each electrically connected to the oxide semiconductor layer;
a gate electrode;
an insulating film between the gate electrode and a stack of the first metal oxide layer, the oxide semiconductor layer, and the second metal oxide layer;
a first low-resistance region between the source electrode and the oxide semiconductor layer; and
a second low-resistance region between the drain electrode and the oxide semiconductor layer,
wherein the oxide semiconductor layer comprises indium,
wherein the first low-resistance region is in contact with the source electrode,
wherein the second low-resistance region is in contact with the drain electrode,
wherein the first low-resistance region has a resistance lower than a region between the first low-resistance region and the second low-resistance region, and
wherein the second low-resistance region has a resistance lower than the region between the first low-resistance region and the second low-resistance region.
2 . The semiconductor device according to claim 1 , wherein the first low-resistance region and the second low-resistance region are located in the second metal oxide layer.
3 . The semiconductor device according to claim 1 , wherein the first low-resistance region and the second low-resistance region are located in the oxide semiconductor layer.
4 . The semiconductor device according to claim 1 , wherein each of the first low-resistance region and the second low-resistance region is lower in resistance than the second metal oxide layer.
5 . The semiconductor device according to claim 1 , wherein the source electrode and the drain electrode comprise a conductive material that has a higher oxygen affinity than metal element in the first metal oxide layer, the oxide semiconductor layer, or the second metal oxide layer.
6 . The semiconductor device according to claim 1 , wherein the source electrode and the drain electrode comprise at least any one of aluminum, chromium, copper, tantalum, molybdenum, and tungsten.
7 . The semiconductor device according to claim 1 ,
wherein the first metal oxide layer, the oxide semiconductor layer, and the second metal oxide layer each comprise indium, gallium, and zinc, and
wherein the first metal oxide layer and the second metal oxide layer comprises gallium more than the oxide semiconductor layer.
8 . The semiconductor device according to claim 1 , wherein the oxide semiconductor layer has a bottom of a conduction band lower than the first metal oxide layer and the second metal oxide layer.
9 . The semiconductor device according to claim 1 , wherein the gate electrode is located over the second metal oxide layer.
10 . The semiconductor device according to claim 1 , wherein the first metal oxide layer is located over the gate electrode.
11 . A semiconductor device comprising:
a first metal oxide layer;
an oxide semiconductor layer over the first metal oxide layer;
a second metal oxide layer over the oxide semiconductor layer;
a source electrode and a drain electrode each over the second metal oxide layer;
a gate electrode;
an insulating film between the gate electrode and a stack of the first metal oxide layer, the oxide semiconductor layer, and the second metal oxide layer;
a first low-resistance region between the source electrode and the oxide semiconductor layer; and
a second low-resistance region between the drain electrode and the oxide semiconductor layer,
wherein the oxide semiconductor layer comprises indium,
wherein the source electrode and the drain electrode are electrically connected to the oxide semiconductor layer,
wherein the first low-resistance region is in contact with the source electrode,
wherein the second low-resistance region is in contact with the drain electrode,
wherein the first low-resistance region has a resistance lower than a region between the first low-resistance region and the second low-resistance region, and
wherein the second low-resistance region has a resistance lower than the region between the first low-resistance region and the second low-resistance region.
12 . The semiconductor device according to claim 11 , wherein the first low-resistance region and the second low-resistance region are located in the second metal oxide layer.
13 . The semiconductor device according to claim 11 , wherein the first low-resistance region and the second low-resistance region are located in the oxide semiconductor layer.
14 . The semiconductor device according to claim 11 , wherein each of the first low-resistance region and the second low-resistance region is lower in resistance than the second metal oxide layer.
15 . The semiconductor device according to claim 11 , wherein the source electrode and the drain electrode comprise a conductive material that has a higher oxygen affinity than metal element in the first metal oxide layer, the oxide semiconductor layer, or the second metal oxide layer.
16 . The semiconductor device according to claim 11 , wherein the source electrode and the drain electrode comprise at least any one of aluminum, chromium, copper, tantalum, molybdenum, and tungsten.
17 . The semiconductor device according to claim 11 ,
wherein the first metal oxide layer, the oxide semiconductor layer, and the second metal oxide layer each comprise indium, gallium, and zinc, and
wherein the first metal oxide layer and the second metal oxide layer comprises gallium more than the oxide semiconductor layer.
18 . The semiconductor device according to claim 11 , wherein the oxide semiconductor layer has a bottom of a conduction band lower than the first metal oxide layer and the second metal oxide layer.
19 . The semiconductor device according to claim 11 , wherein the gate electrode is located over the second metal oxide layer.
20 . The semiconductor device according to claim 11 , wherein the first metal oxide layer is located over the gate electrode.
21 . A semiconductor device comprising:
a first metal oxide layer;
an oxide semiconductor layer over the first metal oxide layer;
a source electrode and a drain electrode over the oxide semiconductor layer;
a second metal oxide layer over the source electrode and the drain electrode;
a gate electrode;
an insulating film between the gate electrode and a stack of the first metal oxide layer, the oxide semiconductor layer, and the second metal oxide layer;
a first low-resistance region between the source electrode and the oxide semiconductor layer; and
a second low-resistance region between the drain electrode and the oxide semiconductor layer,
wherein the oxide semiconductor layer comprises indium,
wherein the source electrode and the drain electrode are electrically connected to the oxide semiconductor layer,
wherein the first low-resistance region is in contact with the source electrode,
wherein the second low-resistance region is in contact with the drain electrode,
wherein the first low-resistance region has a resistance lower than a region between the first low-resistance region and the second low-resistance region, and
wherein the second low-resistance region has a resistance lower than the region between the first low-resistance region and the second low-resistance region.
22 . The semiconductor device according to claim 21 , wherein the first low-resistance region and the second low-resistance region are located in the second metal oxide layer.
23 . The semiconductor device according to claim 21 , wherein the first low-resistance region and the second low-resistance region are located in the oxide semiconductor layer.
24 . The semiconductor device according to claim 21 , wherein each of the first low-resistance region and the second low-resistance region is lower in resistance than the second metal oxide layer.
25 . The semiconductor device according to claim 21 , wherein the source electrode and the drain electrode comprise a conductive material that has a higher oxygen affinity than metal element in the first metal oxide layer, the oxide semiconductor layer, or the second metal oxide layer.
26 . The semiconductor device according to claim 21 , wherein the source electrode and the drain electrode comprise at least any one of aluminum, chromium, copper, tantalum, molybdenum, and tungsten.
27 . The semiconductor device according to claim 21 ,
wherein the first metal oxide layer, the oxide semiconductor layer, and the second metal oxide layer each comprise indium, gallium, and zinc, and
wherein the first metal oxide layer and the second metal oxide layer comprises gallium more than the oxide semiconductor layer.
28 . The semiconductor device according to claim 21 , wherein the oxide semiconductor layer has a bottom of a conduction band lower than the first metal oxide layer and the second metal oxide layer.
29 . The semiconductor device according to claim 21 , wherein the gate electrode is located over the second metal oxide layer.
30 . The semiconductor device according to claim 21 , wherein the first metal oxide layer is located over the gate electrode.