Design considerations on high sensitivity mos area image sensor

By clarifying the design approach of the photoelectric conversion of the two-dimensional MOS solid-state image sensor, a 320 × 244 element high responsivity MOS sensor has been fabricated and characterized. In the design of the photodiode design formulas for sensing capacity, responsivity and spectral response are presented and are in good agreement with the measurement. In order to suppress blooming without lowering the responsivity, the threshold voltage of the vertical switch transistor is raised and the photodiode whose n+-diffusion layer of the signal wire is surrounded by the p+-layer is proposed. In the horizontal switch transistor design, the signal reading residue is obtained and a simple formula describing the vertical resolution affected by the residue is also obtained. The main features of the MOS sensor developed by this design approach are: (1) high responsivity; (2) high resolution; and (3) strong blooming. The main characteristics are: for 1.4 μA saturation signal current, 71x saturation faceplate illumination (by Tungsten source) at 550 nm, the responsivity is 0.22 μA/μW, horizontal resolution is 240 TV lines, vertical resolution 190 TV lines and dissipation power is 30 mW.