Photoelectric converter having a light receiving portion with an improved readout gate

Abstract

A photoelectric converter with improved charge transfer efficiency from a light receiving portion. The photoelectric converter includes a light receiving portion having an output end and a gate portion having a first side and a second side that both define a readout gate width for the light receiving portion, where the first side of the gate portion confronts the output end of the light receiving portion. The photoelectric converter also includes a charge transfer portion formed to confront the second side of the gate portion, where the readout gate width of said gate portion is wider at the first side confronting said light receiving portion than at the second side confronting said charge transfer portion.

1. A photoelectric converter comprising:
 a light receiving portion  photodiode portion having an output end;  
 a gate portion having a first side and a second side that both define , said gate portion having a readout gate width that varies between said first and second sides, the first side confronting the output end of the light receiving portion  photodiode portion and the second side being opposite the first side, the gate portion corresponding to a single photodiode; and  
 a charge transfer portion formed to confront the second side of the gate portion, wherein the readout gate width of said gate portion is wider at the first side confronting said light receiving portion  photodiode portion than at the second side confronting said charge transfer portion.  
 
     
     
       2. The photoelectric converter according to  claim 1 , wherein said readout gate width narrows linearly proceeding from said light receiving portion  photodiode portion toward said charge transfer portion. 
     
     
       3. The photoelectric converter according to  claim 1 , wherein said gate portion comprises a first gate portion having a first readout gate width of  which is narrower  narrows proceeding from said light receiving portion  photodiode portion toward said transfer portion, and a second gate portion having a second readout gate width that is constant proceeding from said first gate portion towards  toward said charge transfer portion. 
     
     
       4. The photoelectric converter according to  claim 1 , wherein said photoelectric converter is constructed as an imaging apparatus in which said light receiving portion includes  having a plurality of pixels and said charge transfer portion includes  a plurality of charge coupled devices. 
     
     
       5. The photoelectric converter according to  claim 1 , wherein said light receiving portion includes  comprising a plurality of photodiodes. 
     
     
       6. The photoelectric converter according to  claim 1 , wherein said readout gate width narrows curvedly proceeding from said light receiving portion  photodiode portion toward said charge transfer portion. 
     
     
       7. The photoelectric converter according to  claim 1 , wherein said readout gate width narrows gradually proceeding from said light receiving portion  photodiode portion toward said charge transfer portion. 
     
     
       8. The photoelectric converter according to  claim 1 , wherein said charge transfer portion includes charge coupled devices electrically connected along a vertical axis of the photoelectric converter and disposed adjacent to the gate portion. 
     
     
       9. The photoelectric converter according to  claim 1 , wherein said gate portion comprises a barrier gate portion and a readout gate portion having the first and the second sides of the gate portion, the barrier portion is disposed between said charge transfer portion and said light receiving portion  photodiode portion and has a tapered side defined by the readout gate width of the readout gate portion. 
     
     
       10. The photoelectric converter according to  claim 1 , wherein said gate portion substantially prevents leaking of a charge held by the light receiving portion  photodiode portion when said gate portion is in an OFF state. 
     
     
       11. A photoelectric converter comprising:
   a photodiode portion having an output end; and        a gate portion having a first side and a second side, the gate portion having a readout gate width that varies between the first and second sides, the first side confronting the output end of the photodiode portion and the second side being opposite the first side, the gate portion corresponding to a single photodiode;        wherein the readout gate width of the gate portion is wider at the first side than at the second side.     
     
     
       12. The photoelectric converter according to  claim 11 , wherein said readout gate width of the gate portion narrows linearly proceeding from the first side toward the second side. 
     
     
       13. The photoelectric converter according to  claim 11 , comprising a plurality of pixels. 
     
     
       14. The photoelectric converter according to  claim 11 , wherein the photodiode portion includes photodiodes. 
     
     
       15. The photoelectric converter according to  claim 11 , wherein the readout gate width of the gate portion narrows curvedly proceeding from the first side toward the second side. 
     
     
       16. The photoelectric converter according to  claim 11 , wherein the readout gate width of the gate portion narrows gradually proceeding from the first side toward the second side. 
     
     
       17. The photoelectric converter according to  claim 11 , wherein said gate portion substantially prevents leaking of a charge held by the photodiode portion when the gate portion is in an OFF state. 
     
     
       18. The photoelectric converter according to  claim 11 , wherein the first side has same width as a width of the photodiode portion.