The Transverse Field Detector (TFD): A Novel Color-Sensitive CMOS Device

A novel color-sensitive semiconductor detector is proposed. The device [named transverse field detector (TFD)] can be used to measure the color of the incident light without any color filter. The working principle is based on the capability of this device to collect the carriers, generated at different depths, at different superficial junctions by means of suitable transverse electric fields. Due to the differences in the semiconductor light absorption coefficient at different wavelengths, this device can perform color separation. The transverse components of the electric fields are generated inside the semiconductor depleted region by a suitable bias of the superficial collecting junctions. Devices with three or more collecting junctions can be implemented. This new type of color detector takes advantages from CMOS compatibility and technology scaling. The TFD is suitable to be integrated in a pixel array for imaging purposes. First results on a test device built in a completely standard CMOS 90-nm technology are shown.