Semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorHajime KIMURA
Life of this patent
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Abstract
It is an object to provide a semiconductor device which has a large size and operates at high speed. A top gate transistor which includes a semiconductor layer of single-crystal and a bottom gate transistor which includes a semiconductor layer of amorphous silicon (microcrystalline silicon) are formed over the same substrate. Then, gate electrodes of each transistor are formed with the same layer, and source and drain electrodes are also formed with the same layer. Thus, manufacturing steps are reduced. In other words, two types of transistors can be manufactured by adding only a few steps to the manufacturing process of a bottom gate transistor.
Claims1
A semiconductor device comprising:
- a first semiconductor layer over an insulating substrate;
- a first insulating layer over the first semiconductor layer;
- a first conductive layer and a second conductive layer over the first insulating layer;
- a second insulating layer over the first conductive layer and the second conductive layer;
- a second semiconductor layer over the second insulating layer;
- and
- a third conductive layer over the second semiconductor layer,
- wherein the first conductive layer is overlapped with the first semiconductor layer, and the second conductive layer is overlapped with the second semiconductor layer;
- wherein the first semiconductor layer serves as an active layer of a first transistor;
- wherein the second semiconductor layer serves as an active layer of a second transistor;
- and
- wherein a property of the first semiconductor layer is different from a property of the second semiconductor layer.
Dependencies are inferred from the claim text.