Characterization of fault tolerant and duo-output active pixel sensors

The Fault Tolerant Active Pixel Sensor (FTAPS) corrects for defects by operating two pixel halves in parallel and retaining half sensitivity when affected by a point defect. Photodiode and photogate FTAPS devices were fabricated in 0.35µm technology and behaved as expected with and without defects. The photodiode FTAPS was almost twice as sensitive as a standard Active Pixel Sensor (APS) and 0.18µm technology pixels were about half as sensitive as 0.35µm technology pixels. The photodiode FTAPS noise was calculated to be greater than a standard APS, however the FTAPS signal-to-noise ratio remained on par with the standard APS due to increased sensitivity. A detection algorithm was developed for identifying standard APS and FTAPS defects from statistical analysis of the images taken. A Duo-output Active Pixel Sensor (DAPS) performed background subtraction, however crosstalk from charge collection of the parasitic n+ diffusion degraded its performance.