Imaging device and electronic device

1. An imaging device comprising:

a first semiconductor substrate provided with pixels including a photoelectric conversion element and floating diffusion that temporarily holds a charge output from the photoelectric conversion element; and

a semiconductor layer provided on the first semiconductor substrate via an insulating film, the semiconductor layer including a readout circuit unit that reads out the charge held in the floating diffusion and outputs a pixel signal,

wherein the semiconductor layer is formed of an organic semiconductor material.

2. The imaging device according to claim 1 , wherein the organic semiconductor material is one material selected from a material group consisting of a tetracene material, a naphthalene material, a pentacene material, a rubrene material, a thienoacene material, a polythiophene material, a polyfluorene material, and a polyhexylophene material.

3. An imaging device comprising:

a first semiconductor substrate provided with pixels including a photoelectric conversion element and floating diffusion that temporarily holds a charge output from the photoelectric conversion element; and

a semiconductor layer provided on the first semiconductor substrate via an insulating film, the semiconductor layer including a readout circuit unit that reads out the charge held in the floating diffusion and outputs a pixel signal,

wherein the semiconductor layer includes an epitaxial growth layer obtained by epitaxial growth on a front surface of the first semiconductor substrate exposed from an opening provided in the insulating film.

4. The imaging device according to claim 3 , wherein the epitaxial growth layer includes a homoepitaxial growth layer obtained by homoepitaxial growth.

5. The imaging device according to claim 4 , wherein

the first semiconductor substrate is formed with a silicon substrate, and

the epitaxial growth layer is formed of a silicon material.

6. The imaging device according to claim 3 , wherein the epitaxial growth layer includes a heteroepitaxial growth layer obtained by heteroepitaxial growth.

7. The imaging device according to claim 3 ,

wherein the epitaxial growth layer is partially provided above a surface of the insulating film opposite to a surface facing the first semiconductor substrate.

8. The imaging device according to claim 7 , wherein

a plurality of openings is in the insulating film, and

the plurality of openings include the opening.

9. The imaging device according to claim 8 , wherein the epitaxial growth layer has a crystal defect above the insulating film.

10. The imaging device according to claim 3 ,

wherein in a cross section of the imaging device made by cutting along a stacking direction of the imaging device, the opening has a tapered shape in which an opening width narrows from an upper surface side of the insulating film toward a front surface of the semiconductor layer corresponding to a bottom surface of the opening.

11. The imaging device according to claim 1 , wherein the semiconductor layer includes:

a first interlayer insulating film provided on a side of the semiconductor layer opposite to a surface facing the first semiconductor substrate; and

a first metal pad formed of a copper material and provided on a side of the first interlayer insulating film opposite to a surface facing the semiconductor layer.

12. The imaging device according to claim 11 , further comprising a second semiconductor substrate including a logic circuit that processes the pixel signal, the second semiconductor substrate being located on an opposite side of a surface of the semiconductor layer facing the first semiconductor substrate.

13. The imaging device according to claim 12 , wherein the second semiconductor substrate includes:

a second interlayer insulating film provided on a side of a surface of the second semiconductor substrate facing the semiconductor layer; and

a second metal pad formed of a copper material and provided on a side of a surface of the second interlayer insulating film facing the semiconductor layer, and

the semiconductor layer and the second semiconductor substrate are bonded to each other by bonding between the first metal pad and the second metal pad.

14. The imaging device according to claim 1 , further comprising a through-substrate electrode penetrating the semiconductor layer, the through-substrate electrode being configured to electrically connect the floating diffusion and the readout circuit unit to each other.

15. The imaging device according to claim 14 , wherein

the first semiconductor substrate includes a plurality of the pixels, and

the through-substrate electrode is provided in common to the plurality of pixels.

16. The imaging device according to claim 1 ,

wherein the first semiconductor substrate further includes a transfer transistor that transfers the charge output from the photoelectric conversion element to the floating diffusion.

17. The imaging device according to claim 1 , wherein the readout circuit unit includes:

a reset transistor that resets a potential of the floating diffusion to a predetermined potential;

an amplification transistor that outputs the pixel signal in accordance with an amount of the charge held in the floating diffusion; and

a selection transistor that controls a timing of outputting the pixel signal from the amplification transistor.

18. An electronic device that is equipped with an imaging device, the imaging device comprising:

a first semiconductor substrate provided with pixels including a photoelectric conversion element and floating diffusion that temporarily holds a charge output from the photoelectric conversion element; and

a semiconductor layer provided on the first semiconductor substrate via an insulating film, the semiconductor layer including a readout circuit unit that reads out the charge held in the floating diffusion and outputs a pixel signal,

wherein the semiconductor layer is formed of an organic semiconductor material.