Solid state imaging device, method for driving the same and camera using the same

Abstract

In making solid state imaging devices smaller and increasing their number of pixels, it is desirable to increase the charge amount that can be handled per unit area of the transfer portions. It is possible to achieve this by making the insulating film thinner, but this leads to electric fields in the semiconductor substrate that are too strong, and causes problems such as the generation of noise and the deterioration of the transfer efficiency. This invention relaxes potential steps in the transfer region by applying, when a signal charge 1 is being read out (t=t 2 ), a high voltage to the electrode 43 for reading out the signal charge, a low voltage to at least one of the electrodes 41, 45 - 47 for preventing unnecessary mixing of signal charges, and an intermediate voltage between the high voltage and the low voltage to the electrodes 42 and 44 , which are adjacent to the electrode 43 to which the high voltage is applied.

1 - 28 . (canceled)  
   
   
       29 . A method for driving a solid state imaging device comprising a plurality of light-receiving portions formed in a semicondutctor substrate, a transfer region formed alongside a colum of said light-receiving portions in said semiconductor substrate, and transfer electrodes made of a plurality of electrode groups arranged repeatedly on said transfer region, wherein each of the electrode groups includes at least six adjacent electrodes, and voltage patterns that are independent of each other are applied to the respective electrodes of each of the electrode groups, 
 the method comprising reading out signal charges accumulated in said light-receiving portions from said light-receiving portions to said transfer region; and transferring the signal charges in the transfer region while applying voltage to said transfer electrodes; and    at a time when the signal charges are being read out to said transfer region, 
 (i) applying a read-out voltage V H  to the electrodes corresponding to those light-receiving portions that include signal charges to be read out;  
 (ii) applying a barrier voltage V L  that is lower than the read-out voltage V H  to at least one of said electrodes, which is located between the electrodes to which the read-out voltage V H  is being applied and which is not adjacent to the electrodes to which the read-out voltage V H  is being applied; and  
 (iii) applying an intermediate voltage V M  that is lower than the read-out voltage V H  and higher than the barrier voltage V L  to those electrodes that are adjacent to the electrodes to which the read-out voltage V H  is being applied.  
   
   
   
       30 . A method for driving a solid state imaging device comprising a plurality of light-receiving portions formed in a semiconductor substrate, a transfer region formed alongside a column of said light-receiving portions in said semiconductor substrate, and transfer electrodes made of a plurality of electrode groups arranged repeatedly on said transfer region, wherein each of the electrode groups includes six adjacent electrodes, and voltage patterns that are independent of each other are applied to the respective electrodes of each of the electrode groups, 
 the method comprising reading out signal charges accumulated in said light-receiving portions from said light-receiving portions to said transfer region; and transferring the signal charges in the transfer region while applying voltage to said transfer electrodes; and    at a time when the signal charges are being read out to said transfer region,    and lasting for a said period starting at a predetermined period of time before the beginning of an application of a read-out voltage V II  to the electrodes corresponding to those light-receiving portions that include signal charges to be read out and ending when the application of a read-out voltage V H  is terminated,    applying, to those electrodes corresponding to the light-receiving portions that are adjacent to those light-receiving portions that include signal charges to be read out, a voltage change that is opposing to a voltage change occurring when the read-out voltage V H  is applied.    
   
   
       31 . A method for driving a solid state imaging device comprising a plurality of light-receiving portions formed in a semiconductor substrate, a transfer region formed alongside a column of said light-receiving portions in said semiconductor substrate, and transfer electrodes made of a plurality of electrode groups arranged repeatedly on said transfer region, wherein each of the electrode groups includes at least six adjacent electrodes, and voltage patterns that are independent of each other are applied to the respective electrodes of each of the electrode groups, 
 the method comprising reading out signal charges accumulated in said light-receiving portions from said light-receiving portions to said transfer region; and transferring the signal charges in the transfer region while applying voltage to said transfer electrodes; and    at a time when the signal charges are being read out to said transfer region,    and lasting for a period starting at a predetermined period of time before the beginning of an application of a read-out voltage V H  to the electrodes corresponding to those light-receiving portions that include signal charges to be read out and ending when the application of a read-out voltage V H  is terminated,    applying, to those electrodes to which the read-out voltage V H  is not applied and which are not adjacent to the electrodes to which the read-out voltage V H  is applied, a voltage change that is opposite to a voltage change occurring when the read-out voltage V H  is applied.