A study on γ characteristics on logarithmic conversion of photo current to voltage : Short title : Logarithmic conversion of photo current to voltage

Abstract

Logarithmic conversions of photo current to voltage have been tried to increase dynamic range of image sensors. The conversion had succeeded only when sub threshold region V_G-I_D characteristics of MOS transistor was used. It was clarified in this paper that various γ characteristics (the slope of logarithmic photo current to gate voltage) can be achieved in MOS transistors with non-uniform substrate impurity concentrations and various buried channel transistors.