V.A. Wright

Simulation Results From Double-Sided 3-D Detectors

A new ldquodouble sidedrdquo 3-D solid-state detector structure, intended to simplify the 3-D fabrication process, is proposed. In this structure, electrode columns of different doping types are etched from opposite sides of the substrate, with neither set of columns passing through the full substrate thickness. The finite-element simulation package ISE-TCAD is used to determine the performance of this structure. The double-sided detector shows similar electrostatic behavior to a standard 3-D detector, giving a low depletion voltage and fast charge collection. However, unless the electrode column length is very close to the substrate thickness, charge deposited around the front and back surfaces of the device is collected less quickly (though still rapidly compared with a planar geometry device). The breakdown voltage is dominated by high-field regions around the tips of the electrode columns and shows little change when the oxide charge is increased.

Three-dimensional Medipix-a new generation of X-ray detectors

Three-dimensional (3-D) detectors have many potential advantages over standard planar devices and for a range of applications, e.g., high energy physics, synchrotron radiation detection and medical imaging. One such area is minimizing the effects due to charge sharing between adjacent pixels. Simulations of pixel detector compatible with the Medipix2 chip show that 3-D detectors have significant advantages in this area. In addition, a 64/spl times/64 pixel 3-D detector designed for read-out by the Medipix1 chip has been fabricated. The sensors have been characterized using current-voltage and capacitance measurements. They are currently being bump-bonded to the Medipix1 chip at the University of Freiburg in order for the complete system to be evaluated using a X-ray source.