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US 11,107,928 B2Granted
Semiconductor device and method for manufacturing the same
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsKengo Akimoto, Toshinari Sasaki
Life of this patent
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Abstract
An object is to improve field effect mobility of a thin film transistor using an oxide semiconductor. Another object is to suppress increase in off current even in a thin film transistor with improved field effect mobility. In a thin film transistor using an oxide semiconductor layer, by forming a semiconductor layer having higher electrical conductivity and a smaller thickness than the oxide semiconductor layer between the oxide semiconductor layer and a gate insulating layer, field effect mobility of the thin film transistor can be improved, and increase in off current can be suppressed.
Claims20
A semiconductor device comprising:
- a gate electrode;
- a gate insulating layer over the gate electrode;
- a first non-single crystalline oxide semiconductor layer comprising indium and zinc over the gate electrode with the gate insulating layer interposed therebetween;
- a second non-single crystalline oxide semiconductor layer comprising indium and zinc over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having an electrical conductivity lower than the first non-single crystalline oxide semiconductor layer;
- a source electrode over the second non-single crystalline oxide semiconductor layer, the source electrode comprising a conductive layer comprising copper;
- a drain electrode over the second non-single crystalline oxide semiconductor layer, the drain electrode comprising a conductive layer comprising copper;
- and
- a first insulating film comprising silicon and oxygen over the second non-single crystalline oxide semiconductor layer, the source electrode and the drain electrode,
- wherein part of the second non-single crystalline oxide semiconductor layer between the source electrode and the drain electrode is etched so that a portion of the second non-single crystalline oxide semiconductor layer between the source electrode and the drain electrode is thinner than portions of the second non-single crystalline oxide semiconductor layer below the source electrode and the drain electrode,
- wherein the first insulating film is in contact with an upper surface of the second non-single crystalline oxide semiconductor layer between the source electrode and the drain electrode, and
- wherein the first non-single crystalline oxide semiconductor layer is thinner than the second non-single crystalline oxide semiconductor layer.
8 more elements
A semiconductor device comprising:
- a gate electrode;
- a gate insulating layer over the gate electrode;
- a first non-single crystalline oxide semiconductor layer comprising indium and, zinc over the gate electrode with the gate insulating layer interposed therebetween;
- a second non-single crystalline oxide semiconductor layer comprising indium and zinc over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having an electrical conductivity lower than the first non-single crystalline oxide semiconductor layer;
- a source electrode over the second non-single crystalline oxide semiconductor layer through a first n-type conductivity region, the source electrode comprising a conductive layer comprising copper;
- a drain electrode over the second non-single crystalline oxide semiconductor layer through a second n-type conductivity region, the drain electrode comprising a conductive layer comprising copper;
- and
- a first insulating film comprising silicon and oxygen over the second non-single crystalline oxide semiconductor layer, the source electrode and the drain electrode,
- wherein part of the second non-single crystalline oxide semiconductor layer between the source electrode and the drain electrode is etched so that a portion of the second non-single crystalline oxide semiconductor layer between the source electrode and the drain electrode is thinner than portions of the second non-single crystalline oxide semiconductor layer below the source electrode and the drain electrode,
- wherein the first insulating film is in contact with an upper surface of the second non-single crystalline oxide semiconductor layer between the source electrode and the drain electrode, and
- wherein each of the first n-type conductivity region and the second n-type conductivity region comprises indium.
8 more elements
A semiconductor device comprising:
- a gate electrode;
- a gate insulating layer over the gate electrode;
- a first non-single crystalline oxide semiconductor layer comprising indium and zinc over the gate electrode with the gate insulating layer interposed therebetween;
- a second non-single crystalline oxide semiconductor layer comprising indium and zinc over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having an electrical conductivity lower than the first non-single crystalline oxide semiconductor layer;
- a source electrode over with the second non-single crystalline oxide semiconductor layer, the source electrode comprising a conductive layer comprising copper;
- a drain electrode over with the second non-single crystalline oxide semiconductor layer, the drain electrode comprising a conductive layer comprising copper;
- and
- a first insulating film comprising silicon and oxygen over the second non-single crystalline oxide semiconductor layer, the source electrode and the drain electrode,
- wherein the first insulating film is in contact with an upper surface of the second non-single crystalline oxide semiconductor layer between the source electrode and the drain electrode, and
- wherein the first non-single crystalline oxide semiconductor layer is thinner than the second non-single crystalline oxide semiconductor layer.
7 more elements
Dependencies are inferred from the claim text.