Novel Device Concept for Voltage-Bias Controlled Color Detection in Amorphous Silicon Sensitized Cmos Cameras

Abstract

We present a novel sensor concept comprising a new contacting scheme for voltage-bias con- trolled thin film photodiode arrays on CMOS readout chips. Our unilateral contact structure greatly facilitates manufacturing of the sensor system. Moreover, the novel contacting scheme most efficiently suppresses crosstalk between neighboring pixels. The respective devices are ready for operation and testing directly after deposition of the amorphous silicon based sensor layers. No extra transparent front contact is needed, no patterning and no connection between the topmost layer of the thin film stack and the underlying readout chip. Due to the lack of a metal oxide front contact, contamination of CMOS manufacturing equipment with tin, zinc or similar materials is definitely avoided. Thus, for the first time, a sensor concept with complete CMOS process compatibility is demonstrated. Our new sensor structure allows for a considerable reduction in manufacturing cost of high performance optical detection systems. As a proof of concept, we present detailed investiga- tions on current-voltage characteristics, dynamic behavior and spectral response of 0.1-inch test structures. Down-scaling to pixel sizes in the micron range is evaluated by semi-empirical numerical modeling and proves easily feasible.

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