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Three hydrogenated amorphous silicon photodiodes stacked for an above integrated circuit colour sensor
Author(s) -
Gidon Pierre,
Giffard Benoit,
Moussy Norbert,
Parrein Pascale,
Poupinet Ludovic
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200982716
Subject(s) - photodiode , amorphous silicon , materials science , pixel , optics , optoelectronics , amorphous solid , signal (programming language) , diode , stack (abstract data type) , silicon , noise (video) , crystalline silicon , physics , computer science , chemistry , organic chemistry , artificial intelligence , image (mathematics) , programming language
We present theoretical simulation and experimental results of a new colour pixel structure. This pixel catches the light in three stacked amorphous silicon photodiodes encompassed between transparent electrodes. The optical structure has been simulated for signal optimisation. The thickness of each stacked layer is chosen in order to absorb the maximum of light and the three signals allow to linearly calculate the CIE colour coordinates 1 with minimum error and noise. The whole process is compatible with an above integrated circuit (IC) approach. Each photodiode is an n‐i‐p structure. For optical reason, the upper diode must be controlled down to 25 nm thickness. The first test pixel structure allows a good recovering of colour coordinates. The measured absorption spectrum of each photodiode is in good agreement with our simulations. This specific stack with three photodiodes per pixel totalises two times more signal than an above IC pixel under a standard Bayer pattern 2,3. In each square of this GretagMacbeth chart is the reference colour on the right and the experimentally measured colour on the left with three amorphous silicon photodiodes per pixel.