PIN detector arrays and integrated readout circuitry on high-resistivity float-zone silicon

A new silicon pin-diode-based pixel detector for ionizing particles integrating a two-dimensional array of detecting elements with readout circuitry has been developed and extensively tested. The signal charge is collected on a low-capacitance electrode avoiding loss of charge into the local readout circuitry within each pixel. The spatial resolution for a given circuitry size is optimized. The approach required back side patterning of the wafer, the only nonconventional part in the Stanford BiCMOS based manufacturing process. Thirteen masks on the front side of the wafer and three on the back yielded both CMOS readout circuitry and detecting elements. A gettering step helped obtain a high minority carrier lifetime (500 μs). Test results obtained by infrared illumination, gamma rays, and high-energy particles, which have been described in detail elsewhere, are summarized. They include a signal to single-channel-noise performance of about 150 to 1 for a minimum ionizing particle, which is an order of magnitude better than silicon strip detectors currently used, and a record-breaking spatial resolution in the direction of smallest pixel pitch (standard deviation of about 1.8 μm). We describe the device and chip operation of the new detector in detail