Optical sensor
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHongyong Zhang, Masayuki Sakakura
Life of this patent
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Abstract
Disposing the light absorption layer formed in contact with a polycrystal silicon layer of a bottom gate type polycrystal silicon TFT allows a depletion layer formed between drain and channel forming regions to extend further into the inside of the light absorption layer, resulting in collection of photo carriers produced in the depletion layer into the channel forming region. The photo carriers collected into the channel forming region are subsequently collected into the source region to be output as large photocurrents by high mobility of the polycrystal silicon.
Claims12
An optical sensor, comprising:
- a gate electrode over a substrate;
- and
- a polycrystal semiconductor layer comprising silicon formed over said gate electrode with a gate insulating film interposed therebetween, and
- an amorphous semiconductor layer formed in contact with said polycrystal semiconductor layer.
An optical sensor, comprising:
- a gate electrode over a substrate;
- and
- a polycrystal semiconductor layer comprising silicon formed over said gate electrode with a gate insulating film interposed therebetween, said polycrystal semiconductor layer including a source region, a drain region, and a channel forming region,
- wherein an amorphous semiconductor layer is formed in contact with at least said channel forming region and said drain region.
An optical sensor, comprising:
- a gate electrode over a substrate;
- a polycrystal semiconductor layer comprising silicon formed over said gate electrode with a gate insulating film interposed therebetween;
- an amorphous semiconductor layer formed in contact with said polycrystal semiconductor layer;
- and
- a transparent conductive layer formed on said amorphous semiconductor layer.
An optical sensor, comprising:
- a gate electrode over a substrate;
- a polycrystal semiconductor layer comprising silicon formed over said gate electrode with a gate insulating film interposed therebetween;
- an amorphous semiconductor layer formed in contact with said polycrystal semiconductor layer;
- and
- a transparent insulating layer formed on said amorphous semiconductor layer.
An optical sensor, comprising:
- a gate electrode over a substrate;
- a polycrystal semiconductor layer comprising silicon formed over said gate electrode with a gate insulating film interposed therebetween, said polycrystal semiconductor layer including a source region, a drain region, and a channel forming region,
- wherein an amorphous semiconductor layer is formed in contact with at least said channel forming region and said drain region, and wherein a conductive layer with optical transmission properties for visible light is formed on said amorphous semiconductor layer.
An optical sensor, comprising:
- a gate electrode over a substrate;
- a polycrystal semiconductor layer comprising silicon formed over said gate electrode with a gate insulating film interposed therebetween, said polycrystal semiconductor layer including a source region, a drain region, and a channel forming region,
- wherein an amorphous semiconductor layer is formed in contact with at least said channel forming region and said drain region, and wherein an insulating layer with translucent properties for visible light is formed on said amorphous semiconductor layer.
Dependencies are inferred from the claim text.