Title :
A random noise reduction method for an amorphous silicon photoconversion layer overlaid CCD imager
Author :
Nakamura, Nobuo ; Ohsawa, Shinji ; Matsunaga, Yoshiyuki ; Yoshida, Okio
Author_Institution :
Res. & Dev. Center, Toshiba Corp., Kawasaki, Japan
fDate :
10/1/1997 12:00:00 AM
Abstract :
A novel random noise reduction (RNR) method, which can reduce random noise generated in a storage diode (SD), has been proposed and evaluated with a cell test element. The RNR cell structure features an RNR transistor with a second storage diode, which is inserted between the SD and a vertical CCD (V-CCD). The RNR transistor controls the transfer channel potential and suppresses the random noise generated in the SD. Net first storage diode capacitance with the RNR transistor can be reduced down to (Cf×Ca)/(Cf+m×Ca ), where Cf is the second storage diode capacitance, C a is the first storage diode capacitance, and m is the channel potential modulation factor. Experimentally, the RNR cell can reduce the random noise in the SD from 42 electrons [r.m.s.] down to 18 electrons [r.m.s.] for the SD capacitance of 5 fF. This makes it possible for the photoconversion layer overlaid CCD imager with the RNR cells to reproduce video images with a high S/N ratio
Keywords :
CCD image sensors; amorphous semiconductors; capacitance; elemental semiconductors; integrated circuit noise; interference suppression; random noise; silicon; 5 fF; CCD imager; SNR; Si; amorphous Si photoconversion layer; high S/N ratio; noise reduction cell structure; random noise reduction method; storage diode; transfer channel potential control; vertical CCD; video image reproduction; Amorphous silicon; Capacitance; Charge coupled devices; Diodes; Electrons; Image storage; Noise generators; Noise reduction; Semiconductor device noise; Signal to noise ratio;
Journal_Title :
Electron Devices, IEEE Transactions on
