Characterisation of edgeless technologies for pixellated and strip silicon detectors with a micro-focused X-ray beam

Abstract

Reduced edge or ``edgeless'' detector design offers seamless tileability ofsensors for a wide range of applications from particle physics tosynchrotron and free election laser (FEL) facilities and medical imaging.Combined with through-silicon-via (TSV) technology, this would allow reducedmaterial trackers for particle physics and an increase in the active areafor synchrotron and FEL pixel detector systems.In order to quantify the performance of different edgeless fabricationmethods, 2 edgeless detectors were characterized at the Diamond Light Sourceusing an 11 μm FWHM 15 keV micro-focused X-ray beam. The devices undertest were: a 150 μm thick silicon active edge pixel sensor fabricatedat VTT and bump-bonded to a Medipix2 ROIC; and a 300 μm thick siliconstrip sensor fabricated at CIS with edge reduction performed by SCIPP andthe NRL and wire bonded to an ALiBaVa readout system.Sub-pixel resolution of the 55 μm active edge pixels was achieved.Further scans showed no drop in charge collection recorded between thecentre and edge pixels, with a maximum deviation of 5% in chargecollection between scanned edge pixels. Scans across the cleaved andstandard guard ring edges of the strip detector also show no reduction incharge collection. These results indicate techniques such as the scribe,cleave and passivate (SCP) and active edge processes offer real potentialfor reduced edge, tiled sensors for imaging detection applications.