Method for manufacturing semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShunpei Yamazaki
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Abstract
In a transistor including an oxide semiconductor film, a metal oxide film which has a function of preventing electrification and covers a source electrode and a drain electrode is formed in contact with the oxide semiconductor film, and then, heat treatment is performed. Through the heat treatment, impurities such as hydrogen, moisture, a hydroxyl group, or hydride are intentionally removed from the oxide semiconductor film, whereby the oxide semiconductor film is highly purified. By providing the metal oxide film, generation of a parasitic channel on the back channel side of the oxide semiconductor film in the transistor is prevented.
Claims23
A method for manufacturing a semiconductor device, comprising the steps of:
- forming a gate electrode;
- forming a gate insulating film;
- forming an oxide semiconductor film;
- performing a first heat treatment after forming the oxide semiconductor film;
- forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film;
- forming a metal oxide film over and in contact with the oxide semiconductor film;
- and
- performing a second heat treatment after forming the metal oxide film,
- wherein the oxide semiconductor film and the gate electrode overlap with each other with the gate insulating film interposed therebetween, and
- wherein the metal oxide film comprises gallium.
A method for manufacturing a semiconductor device, comprising the steps of:
- forming a gate electrode;
- forming a gate insulating film;
- forming an oxide semiconductor film comprising indium and gallium;
- performing a first heat treatment after forming the oxide semiconductor film;
- forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film;
- forming a metal oxide film over and in contact with the oxide semiconductor film;
- and
- performing a second heat treatment after forming the metal oxide film,
- wherein the oxide semiconductor film and the gate electrode overlap with each other with the gate insulating film interposed therebetween,
- wherein the first heat treatment is performed before forming the metal oxide film, and
- wherein the metal oxide film comprises gallium.
A method for manufacturing a semiconductor device, comprising the steps of:
- forming a gate electrode;
- forming a gate insulating film;
- forming an oxide semiconductor film comprising indium and gallium;
- forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film;
- forming a metal oxide film over and in contact with the oxide semiconductor film;
- and
- supplying oxygen to the oxide semiconductor film from the metal oxide film by performing a heat treatment,
- wherein the oxide semiconductor film and the gate electrode overlap with each other with the gate insulating film interposed therebetween, and
- wherein the metal oxide film comprises gallium.
Dependencies are inferred from the claim text.