THEORY AND MODELING OF THE FLOATING-SURFACE DETECTOR - AN ENHANCED CCD OUTPUT STRUCTURE

In the performance of today's CCD imagers, amplifier noise plays an im portant role. The traditional floating-diffusion amplifier has a relat ively high noise level because its sensing capacitance cannot be made sufficiently small. In order to exploit the CCD most effectively, some alternative output structures with lower noise are under study at thi s moment. The floating-surface detector is one of the most promising s tructures. This detector integrates the detection node into the channe l region of one of the MOS transistors belonging to the output stage. It results in a very low (fixed) sensing capacitance compared with the conventional floating-diffusion amplifier and therefore results in an improved dynamic range of the amplifier. This paper presents an histo rical view of conventional and integrated detectors, and describes the theory and modelling of the floating-surface detector.