Patent ID: 7184083
Filing Date: 2007-02-27
Classification: H01L,H04N

Abstract:
1. A solid state image pickup apparatus comprising: a semiconductor substrate; a number of photoelectric conversion elements formed in one surface of said semiconductor substrate in a matrix shape with a plurality of rows and columns, each of said photoelectric conversion elements accumulating charges corresponding to an amount of incidence light; a first charge transfer device for receiving charges accumulated in each of said photoelectric conversion elements and transferring the charges in a predetermined direction by being driven by pulse voltage trains of a plurality of phases, said first charge transfer device comprising: an electrically insulating film formed on the surface of said semiconductor substrate; a plurality of transfer electrodes disposed in line on the insulating film, said transfer electrodes being classified into a plurality of groups and connected in common in groups; and an n-type charge transfer channel formed in the surface of said semiconductor substrate and traversing each of said transfer electrodes, the n-type charge transfer channel including accumulation regions and barrier regions alternately disposed along the length of the n-type charge transfer channel, a concentration of conductivity-determining impurity in said accumulation regions and in said barrier regions of said n-type charge transfer channel being set to such a level that a potential of said n-type charge transfer channel takes a pinning potential when a predetermined negative voltage is applied to said transfer electrodes; a charge detector circuit electrically connected to an output end of said first charge transfer device for detecting charges output from said first charge transfer device and generating an electrical signal; a first drive circuit for generating pulse voltage trains of a plurality of phases each taking the predetermined negative voltage or a negative voltage near the predetermined negative voltage as a low level; a second charge transfer device comprising: a plurality of vertical charge transfer channels formed in the surface of said semiconductor substrate, each vertical charge transfer channel extending along a photoelectric conversion elements column and having an impurity concentration approximately equal to that of the accumulation regions of the charge transfer channel in the first charge transfer device; and a plurality of transfer electrodes disposed on an electrically insulating film formed above the surface of said semiconductor substrate and traversing the vertical charge transfer channels, said second charge transfer device transferring charges to said first charge transfer device by being driven by negative pulse voltage trains of a plurality of phases each having a negative voltage as a low level voltage; a second drive circuit electrically connected to said second charge transfer device for generating the negative pulse voltage trains of a plurality of phases to be used for driving said second charge transfer device, wherein the pulse voltage trains generated by the first drive circuit and the negative pulse voltage trains generated by the second drive circuit have a high level of ground potential.