Further developments on a novel color sensitive CMOS detector

摘要

The Transverse Field Detector (TFD) is a recently proposed Silicon pixel device designed to perform color imaging without the use of color filters.The color detection principle is based on the dependence of the Silicon absorption coefficient from the wavelength and relies on the generation of a suitable transverse electric field configuration, within the semiconductor active layer, to drive photocarriers generated at different depths towards different collecting electrodes. Each electrode has in this way a different spectral response with respect to the incoming wavelength. Pixels with three or four different spectral responses can be implemented within ～ 6 μm of pixeldimension. Thanks to the compatibility with standard triple well CMOS processes, the TFD can be used in an ActivePixel Sensor exploiting a dedicated readout topology, based on a single transistor charge amplifier. Theoverall APS electronics includes five transistors (5T) and a feedback capacitance, with a resulting overall fillfactor around 50%.In this work the three colors and four colors TFD pixel simulations and implementations in a 90 nm standardCMOS triple well technology are described. Details on the design of a TFD APS mini matrix are providedand preliminary experimental results on four colors pixels are presented.