Semiconductor device and manufacturing method thereof
View Patent ↗A semiconductor device includes an oxide semiconductor layer including a crystalline region over an insulating surface, a source electrode layer and a drain electrode layer in contact with the oxide semiconductor layer, a gate insulating layer covering the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode layer over the gate insulating layer in a region overlapping with the crystalline region. The crystalline region includes a crystal whose c-axis is aligned in a direction substantially perpendicular to a surface of the oxide semiconductor layer.
1. A manufacturing method of a semiconductor device, comprising:
forming an oxide semiconductor layer over an insulating surface;
forming a conductive layer electrically connected to the oxide semiconductor layer;
forming a source electrode layer and a drain electrode layer by etching the conductive layer;
forming a crystalline region in the oxide semiconductor layer by performing heat treatment to align c-axis of the crystalline region in a direction substantially perpendicular to a surface of the oxide semiconductor layer;
forming a gate insulating layer over the oxide semiconductor layer and
forming a gate electrode layer over the gate insulating layer in a region overlapping with the crystalline region.
2. The manufacturing method of a semiconductor device according to claim 1 , wherein the heat treatment is performed at a temperature higher than or equal to 550° C. and lower than or equal to 850° C.
3. The manufacturing method of a semiconductor device according to claim 1 , wherein a part of the oxide semiconductor layer is removed when the conductive layer is etched.
4. The manufacturing method of a semiconductor device according to claim 1 , further comprising a step of forming insulating layers having substantially same shapes as the source electrode layer and the drain electrode layer over the source electrode layer and the drain electrode layer, respectively.
5. The manufacturing method of a semiconductor device according to claim 1 , wherein a portion of the source electrode layer and the drain electrode layer in contact with the oxide semiconductor layer is formed using a material having low oxygen affinity.
6. The manufacturing method of a semiconductor device according to claim 1 , wherein an oxide semiconductor layer having an amorphous structure is formed as the oxide semiconductor layer, and the amorphous structure remains in a region other than the crystalline region.
7. The manufacturing method of a semiconductor device according to claim 1 , wherein the oxide semiconductor layer includes indium and zinc.
8. A manufacturing method of a semiconductor device, comprising:
forming a first gate electrode layer over an insulating surface;
forming a first gate insulating layer over the first gate electrode layer;
forming an oxide semiconductor layer over the first gate insulating layer;
forming a conductive layer electrically connected to the oxide semiconductor layer;
forming a source electrode layer and a drain electrode layer by etching the conductive layer;
forming a crystalline region in the oxide semiconductor layer by performing heat treatment to align c-axis of the crystalline region in a direction substantially perpendicular to a surface of the oxide semiconductor layer;
forming a second gate insulating layer over the oxide semiconductor layer; and
forming a second gate electrode layer over the second gate insulating layer in a region overlapping with the crystalline region.
9. The manufacturing method of a semiconductor device according to claim 8 , wherein the heat treatment is performed at a temperature higher than or equal to 550° C. and lower than or equal to 850° C.
10. The manufacturing method of a semiconductor device according to claim 8 , wherein a part of the oxide semiconductor layer is removed when the conductive layer is etched.
11. The manufacturing method of a semiconductor device according to claim 8 , further comprising a step of forming insulating layers having substantially same shapes as the source electrode layer and the drain electrode layer over the source electrode layer and the drain electrode layer, respectively.
12. The manufacturing method of a semiconductor device according to claim 8 , wherein a portion of the source electrode layer and the drain electrode layer in contact with the oxide semiconductor layer is formed using a material having low oxygen affinity.
13. The manufacturing method of a semiconductor device according to claim 8 , wherein an oxide semiconductor layer having an amorphous structure is formed as the oxide semiconductor layer, and the amorphous structure remains in a region other than the crystalline region.
14. The manufacturing method of a semiconductor device according to claim 8 , wherein the oxide semiconductor layer includes indium and zinc.