Light-receiving element and display device

1. A light-receiving element comprising:

a first-conductivity-type semiconductor region over an element formation surface;

a second-conductivity-type semiconductor region over the element formation surface;

an intermediate semiconductor region over the element formation surface between the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region, and having an impurity concentration lower than impurity concentrations of the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region;

a first electrode electrically connected to the first-conductivity-type semiconductor region;

a second electrode electrically connected to the second-conductivity-type semiconductor region; and

a control electrode in an area opposed to the intermediate semiconductor region on the element formation surface with an insulating film therebetween,

wherein,

a conductivity type of an impurity in the intermediate semiconductor region is an n-type, and

the light-receiving element is configured to operate such that a photocurrent generated in the light-receiving element is controlled through a voltage applied to the control electrode, the applied voltage being a negative potential when the conductivity type of the impurity in the intermediate semiconductor region is the n-type.

2. The light-receiving element according to claim 1 , wherein

the first electrode is an anode electrode and the second electrode is a cathode electrode, and

the cathode electrode or an electrode electrically connected to the cathode electrode has an opposed region that is opposed to the control electrode with intermediary of at least a part of the intermediate semiconductor region.

3. The light-receiving element according to claim 1 , wherein

the control electrode is under the first-conductivity-type semiconductor region, the second-conductivity-type semiconductor region, and the intermediate semiconductor region.

4. The light-receiving element according to claim 1 , wherein

the control electrode is over the first-conductivity-type semiconductor region, the second-conductivity-type semiconductor region, and the intermediate semiconductor region.

5. The light-receiving element according to claim 1 , wherein

the impurity concentration of the intermediate semiconductor region is equal to or lower than 2×10 18 (atm/cm 3 ).

6. The light-receiving element according to claim 1 , wherein

the first-conductivity-type semiconductor region, the second-conductivity-type semiconductor region, and the intermediate semiconductor region include a non-single-crystal semiconductor layer composed of polycrystalline silicon.

7. The light-receiving element according to claim 6 , wherein

thickness of the non-single-crystal semiconductor layer is equal to or larger than 30 nm and equal to or smaller than 60 nm.

8. The light-receiving element according to claim 1 , wherein

a boundary between the intermediate semiconductor region and the second-conductivity-type semiconductor region is positioned above an end of the control electrode closer to the second-conductivity-type semiconductor region, or is positioned closer to an end of the second-conductivity-type semiconductor region on an opposite side to the boundary than the end of the control electrode.

9. A display device including a plurality of arranged display elements and a light-receiving element, the light-receiving element comprising:

a first-conductivity-type semiconductor region over an element formation surface;

a second-conductivity-type semiconductor region over the element formation surface;

an intermediate semiconductor region over the element formation surface between the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region, and having an impurity concentration lower than impurity concentrations of the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region;

a first electrode electrically connected to the first-conductivity-type semiconductor region;

a second electrode electrically connected to the second-conductivity-type semiconductor region; and

a control electrode in an area opposed to the intermediate semiconductor region on the element formation surface with an insulating film therebetween,

wherein,

a conductivity type of an impurity in the intermediate semiconductor region is an n-type, and

the light-receiving element is configured to operate such that a photocurrent generated in the light-receiving element is controlled through a voltage applied to the control electrode, the applied being a negative potential when the conductivity type of the impurity in the intermediate semiconductor region is the n-type.

10. A light-receiving element comprising:

a first-conductivity-type semiconductor region formed over an element formation surface;

a second-conductivity-type semiconductor region formed over the element formation surface;

an intermediate semiconductor region formed over the element formation surface between the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region, and have an impurity concentration lower than impurity concentrations of the first-conductivity-type semiconductor region and the second-conductivity-type semiconductor region;

a first electrode electrically connected to the first-conductivity-type semiconductor region;

a second electrode electrically connected to the second-conductivity-type semiconductor region; and

a control electrode in an area opposed to the intermediate semiconductor region on the element formation surface with an insulating film therebetween,

wherein,

the light-receiving element is configured to operate such that a photocurrent generated in the light-receiving element is controlled through a voltage applied to the control electrode, a potential of the applied voltage being of the same polarity as a conductivity type of an impurity in the intermediate semiconductor region.