Solid-state image pickup device, method of manufacturing solid-state image pickup device, and electronic apparatus

Abstract

There is provided a solid-state image pickup device including: a semiconductor substrate; a photodiode formed in the semiconductor substrate; a transistor having a gate electrode part or all of which is embedded in the semiconductor substrate, the transistor being configured to read a signal electric charge from the photodiode via the gate electrode; and an electric charge transfer layer provided between the gate electrode and the photodiode.

What is claimed: 
     
         1 . A light detecting device, comprising:
 a first photodiode formed in a semiconductor substrate;   a floating diffusion disposed in the semiconductor substrate; and   a gate electrode configured to transfer a signal electric charge from the first photodiode to the floating diffusion, at least a portion of the gate electrode being embedded in the semiconductor substrate, wherein all the first photodiode is disposed below a bottom of the portion of the gate electrode.   
     
     
         2 . The light detecting device according to  claim 1 , wherein the semiconductor substrate comprises a light incident surface, and wherein all of the first photodiode is disposed between the bottom of the portion of the gate electrode and the light incident surface. 
     
     
         3 . The light detecting device according to  claim 1 , wherein the portion of the gate electrode overlaps the first photodiode in a plan view. 
     
     
         4 . The light detecting device according to  claim 1 , further comprising an electric charge transfer layer disposed in the semiconductor substrate, wherein a portion of the electric charge transfer layer is disposed between the first photodiode and the bottom of the portion of the gate electrode. 
     
     
         5 . The light detecting device according to  claim 4 , wherein the electric charge transfer layer is in contact with the first photodiode. 
     
     
         6 . The light detecting device according to  claim 1 , further comprising:
 a second photodiode, wherein the first photodiode is formed at a first depth in the semiconductor substrate and the second photodiode is formed at a second depth in the semiconductor substrate and overlaps with the first photodiode, wherein the first photodiode at the first depth is closer to a light receiving surface of the semiconductor substrate than the second photodiode at the second depth.   
     
     
         7 . The light detecting device according to  claim 1 , wherein the portion of the gate electrode fills a concave section in the semiconductor substrate. 
     
     
         8 . The light detecting device according to  claim 7 , further comprising an electric charge transfer layer disposed in the semiconductor substrate, wherein the electric charge transfer layer is adjacent to and self-aligned with a bottom face of the concave section so that the electric charge transfer layer covers the bottom face but not side faces of the concave section. 
     
     
         9 . The light detecting device according to  claim 8 , wherein the electric charge transfer layer is formed by ion implantation through the bottom face of the concave section. 
     
     
         10 . The light detecting device according to  claim 1 , further comprising:
 an electric charge transfer layer between the first photodiode and the portion of the gate electrode; and   a dark current suppression layer of a different conductivity type than the electric charge transfer layer and between the portion of the gate electrode and the electric charge transfer layer.   
     
     
         11 . An electronic apparatus, comprising:
 a lens;   a signal process circuit; and   a light detecting device, comprising:
 a first photodiode formed in a semiconductor substrate; 
 a floating diffusion disposed in the semiconductor substrate; and 
 a gate electrode configured to transfer a signal electric charge from the first photodiode to the floating diffusion, at least a portion of the gate electrode being embedded in the semiconductor substrate, wherein all of the first photodiode is disposed below a bottom of the portion of the gate electrode. 
   
     
     
         12 . The electronic apparatus according to  claim 11 , wherein the semiconductor substrate comprises a light incident surface, and wherein all of the first photodiode is disposed between the bottom of the portion of the gate electrode and the light incident surface. 
     
     
         13 . The electronic apparatus according to  claim 11 , wherein the portion of the gate electrode overlaps the first photodiode in a plan view. 
     
     
         14 . The electronic apparatus according to  claim 11 , further comprising an electric charge transfer layer disposed in the semiconductor substrate, wherein a portion of the electric charge transfer layer is disposed between the first photodiode and the bottom of the portion of the gate electrode. 
     
     
         15 . The electronic apparatus according to  claim 14 , wherein the electric charge transfer layer is in contact with the first photodiode. 
     
     
         16 . The electronic apparatus according to  claim 11 , further comprising:
 a second photodiode, wherein the first photodiode is formed at a first depth in the semiconductor substrate and the second photodiode is formed at a second depth in the semiconductor substrate and overlaps with the first photodiode, wherein the first photodiode at the first depth is closer to a light receiving surface of the semiconductor substrate than the second photodiode at the second depth.   
     
     
         17 . The electronic apparatus according to  claim 11 , wherein the portion of the gate electrode fills a concave section in the semiconductor substrate. 
     
     
         18 . The electronic apparatus according to  claim 17 , further comprising an electric charge transfer layer disposed in the semiconductor substrate, wherein the electric charge transfer layer is adjacent to and self-aligned with a bottom face of the concave section so that the electric charge transfer layer covers the bottom face but not side faces of the concave section. 
     
     
         19 . The electronic apparatus according to  claim 18 , wherein the electric charge transfer layer is formed by ion implantation through the bottom face of the concave section. 
     
     
         20 . The electronic apparatus according to  claim 11 , further comprising:
 an electric charge transfer layer disposed in the semiconductor substrate between the first photodiode and the portion of the gate electrode; and   a dark current suppression layer of a different conductivity type than the electric charge transfer layer and disposed in the semiconductor substrate between the portion of the gate electrode and the electric charge transfer layer.