Method for manufacturing semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShunpei Yamazaki
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Abstract
Provided are an oxide semiconductor layer in which the number of defects is reduced and a highly reliable semiconductor device including the oxide semiconductor. A first oxide semiconductor layer having a crystal part is formed over a substrate by a sputtering method. A second oxide semiconductor layer is formed by a thermal chemical vapor deposition method over the first oxide semiconductor layer. The second oxide semiconductor layer is formed by epitaxial growth using the first oxide semiconductor layer as a seed crystal. A channel is formed in the second oxide semiconductor layer.
Claims8
A method of manufacturing a semiconductor device, comprising the steps of:
- forming a first oxide semiconductor layer having a crystal part over a substrate by a sputtering method;
- and
- forming a second oxide semiconductor layer by a thermal chemical vapor deposition method,
- wherein the second oxide semiconductor layer is formed by epitaxial growth using the first oxide semiconductor layer as a seed crystal,
- wherein the second oxide semiconductor layer has a region,
- wherein an electron affinity of the region is higher than an electron affinity of the first oxide semiconductor layer,
- wherein the first oxide semiconductor layer comprises In, Ga and Zn, and
- wherein the second oxide semiconductor layer comprises In, Ga and Zn.
A method of manufacturing a semiconductor device, comprising the steps of:
- forming a first oxide semiconductor layer having a crystal part over a substrate by a sputtering method;
- and
- forming a second oxide semiconductor layer by a metal organic chemical vapor deposition method,
- wherein the second oxide semiconductor layer is formed by epitaxial growth using the first oxide semiconductor layer as a seed crystal,
- wherein the second oxide semiconductor layer has a region,
- wherein an electron affinity of the region is higher than an electron affinity of the first oxide semiconductor layer,
- wherein the first oxide semiconductor layer comprises In, Ga and Zn, and
- wherein the second oxide semiconductor layer comprises In, Ga and Zn.
A method of manufacturing a semiconductor device, comprising the steps of:
- forming a first oxide semiconductor layer having a crystal part over a substrate by a sputtering method;
- forming a second oxide semiconductor layer by a thermal chemical vapor deposition method;
- forming a source electrode layer and a drain electrode layer electrically connected to the second oxide semiconductor layer;
- forming a gate insulating layer in contact with the second oxide semiconductor layer;
- and
- forming a gate electrode layer over the gate insulating layer,
- wherein the second oxide semiconductor layer is formed by epitaxial growth using the first oxide semiconductor layer as a seed crystal,
- wherein the second oxide semiconductor layer has a region, and
- wherein an electron affinity of the region is higher than an electron affinity of the first oxide semiconductor layer.
A method of manufacturing a semiconductor device, comprising the steps of:
- forming a gate electrode layer over a substrate;
- forming a gate insulating layer in contact with the gate electrode layer;
- forming a first oxide semiconductor layer having a crystal part by a sputtering method over the gate insulating layer;
- forming a second oxide semiconductor layer by a thermal chemical vapor deposition method;
- and
- forming a source electrode layer and a drain electrode layer electrically connected to the second oxide semiconductor layer,
- wherein the second oxide semiconductor layer is formed by epitaxial growth using the first oxide semiconductor layer as a seed crystal,
- wherein the second oxide semiconductor layer has a region, and
- wherein an electron affinity of the region is higher than an electron affinity of the first oxide semiconductor layer.
Dependencies are inferred from the claim text.