Semiconductor device and manufacturing method thereof
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsAtsuo ISOBE, Toshinari SASAKI, Junichi KOEZUKA, Shunpei YAMAZAKI
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Abstract
It is an object to provide a semiconductor device in which a short-channel effect is suppressed and miniaturization is achieved, and a manufacturing method thereof. A trench is formed in an insulating layer and impurities are added to an oxide semiconductor film in contact with an upper end corner portion of the trench, whereby a source region and a drain region are formed. With the above structure, miniaturization can be achieved. Further, with the trench, a short-channel effect can be suppressed setting the depth of the trench as appropriate even when a distance between a source electrode layer and a drain electrode layer is shortened.
Claims13
(canceled)
A semiconductor device comprising:
- an insulating layer including a first region having a first thickness and a second region having a second thickness smaller than the first thickness, the insulating layer including a trench including a side surface and a bottom surface, the bottom surface being overlapped with the second region;
- an oxide semiconductor film which includes a source region, a drain region and a channel formation region, and which is in contact with the bottom surface and the side surface of the trench and a top surface of the first region;
- a source electrode layer and a drain electrode layer which are electrically connected to the source region and the drain region, respectively;
- a gate insulating layer over the oxide semiconductor film, the source electrode layer and the drain electrode layer;
- and
- a gate electrode layer over the gate insulating layer, the gate electrode layer overlapping with the trench,
- wherein the channel formation region of the oxide semiconductor film is in contact with the side surface and the bottom surface of the trench, the channel formation region including a crystalline region whose c-axis is substantially perpendicular to a surface of the oxide semiconductor film,
- wherein the source region and the drain region of the oxide semiconductor film are in contact with the top surface of the first region and an upper end corner portion where the top surface of the first region intersects the side surface of the trench, and
- wherein the source region and the drain region have higher impurity concentrations than the channel formation region.
A semiconductor device comprising:
- a substrate comprising a single crystal silicon;
- an insulating layer over the substrate, the insulating layer including a first region having a first thickness and a second region having a second thickness smaller than the first thickness, and the insulating layer including a trench including a side surface and a bottom surface, the bottom surface being overlapped with the second region;
- an oxide semiconductor film which includes a source region, a drain region and a channel formation region, and which is in contact with the bottom surface and the side surface of the trench and a top surface of the first region;
- a source electrode layer and a drain electrode layer which are electrically connected to the source region and the drain region, respectively;
- a gate insulating layer over the oxide semiconductor film, the source electrode layer and the drain electrode layer;
- and
- a gate electrode layer over the gate insulating layer, the gate electrode layer overlapping with the trench,
- wherein the channel formation region of the oxide semiconductor film is in contact with the side surface and the bottom surface of the trench, the channel formation region including a crystalline region whose c-axis is substantially perpendicular to a surface of the oxide semiconductor film,
- wherein the source region and the drain region of the oxide semiconductor film are in contact with the top surface of the first region and an upper end corner portion where the top surface of the first region intersects the side surface of the trench, and
- wherein the source region and the drain region have higher impurity concentrations than the channel formation region.
Dependencies are inferred from the claim text.