Design considerations for MOS pixel for single-sided two-dimensional detector

Abstract

We describe a theoretical study of a single-sided two-dimensional read-out pixel structure to be used as a high resolution tracking detector. This pixel, located on the ohmic side of a depleted p-i-n diode, consists of a n-well and a double drain pMOS transistor in the n-well. The outputs from the drain nodes of the pMOS pixels are ganged together to make a strip-like structure. The pixel detector with such transistors has superior characteristics to double-sided strip detectors currently used in high energy physics experiments. It has a built-in amplification action, resulting in high signal-to-noise detection of charged particles. The electronic noise charge is about 388 electrons for 256 pixels ganged together in a line. It has an advantage of a two-dimensional read-out configuration on a single-sided device. Simpler and cheaper fabrication technology can be used to process such a structure on wafers with diameters exceeding the traditional dimension of 4 in. The structure and electronic properties of the pixel detector are described together with descriptions of signal processing, amplification, noise and linearity in terms of fabrication parameters.