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.