Transistor, semiconductor device including the transistor, and manufacturing method of the transistor and the semiconductor device
View Patent ↗To suppress deterioration in electrical characteristics in a transistor including an oxide semiconductor layer or a semiconductor device including the transistor. In a transistor in which a channel layer is formed using an oxide semiconductor, a silicon layer is provided in contact with a surface of the oxide semiconductor layer. Further, the silicon layer is provided in contact with at least a region of the oxide semiconductor layer, in which a channel is formed, and a source electrode layer and a drain electrode layer are provided in contact with regions of the oxide semiconductor layer, over which the silicon layer is not provided.
1. A transistor comprising:
a gate electrode;
a gate insulating layer provided over the gate electrode;
an oxide semiconductor layer provided over the gate insulating layer and overlapping with the gate electrode;
a silicon layer provided over and in contact with a surface of the oxide semiconductor layer; and
a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer.
2. The transistor according to claim 1 ,
wherein the silicon layer is provided over and in contact with a part of the surface of the oxide semiconductor layer, and
wherein the source electrode layer and the drain electrode layer are provided over and in contact with at least a part of the surface of the oxide semiconductor layer, over which the silicon layer is not provided.
3. The transistor according to claim 2 ,
wherein a first low-resistance region serving as a source region is provided in a region of the oxide semiconductor layer, which is in contact with the source electrode layer, and
wherein a second low-resistance region serving as a drain region is provided in a region of the oxide semiconductor layer, which is in contact with the drain electrode layer.
4. The transistor according to claim 1 , wherein the oxide semiconductor layer includes at least one of indium, zinc, and gallium.
5. A semiconductor device comprising the transistor according to claim 1 .
6. A manufacturing method of a transistor, comprising the steps of:
forming a gate electrode over a substrate;
forming a gate insulating layer over the gate electrode;
forming an oxide semiconductor layer over the gate insulating layer so as to overlap with the gate electrode;
forming a silicon layer so as to cover the oxide semiconductor layer;
etching the silicon layer to expose a part of the oxide semiconductor layer;
forming a conductive film over the silicon layer and the oxide semiconductor layer; and
etching the conductive film to form a source electrode layer and a drain electrode layer.
7. The manufacturing method of a transistor according to claim 6 ,
wherein the source electrode layer and the drain electrode layer are formed in contact with at least parts of the exposed oxide semiconductor layer.
8. The manufacturing method of a transistor according to claim 6 , wherein the silicon layer is formed by a DC sputtering method.