Rauschen von a-Si:H-pin-Dioden für TFA-Bildsensorarrays

TFA (Thin Film on ASIC) -imagers combine photodetectors based on amorphous Silicon with integrated circuits in standard ASIC (Application Specific Integrated Circuit) –technology.
Usually a-Si:H p-i-n diodes are employed as photodetectors. The quality of the video signal is on principle limited by the noise of the photodetectors and the noise of the integrated circuits.
The analytic calculation of all noise components at the input of the pixel amplifier and the limitation of DR and SNR are described as a function of pixel area, dark current, photocurrent as well as integration time and presented for various TFA-imagers. An estimation of the trend of DR and SNR for future generations of TFA-imagers with reduced CMOS feature sizes is presented. The increase of all noise components and the increase of the signal voltage with
downscaling contribute to the reduction of DR und SNR. With the scaling the thermal noise increases stronger than the noise of the photocurrent so that the deviation between DR and SNR decreases.