Diamond Detector With Laser-Formed Buried Graphitic Electrodes - Micron-Scale Mapping of Stress and Charge Collection Efficiency
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2019-09-05 |
| Journal | IEEE Sensors Journal |
| Authors | S. Salvatori, M. JakÅ”iÄ, M.C. Rossi, G. Conte, T. V. Kononenko |
| Institutions | Roma Tre University, Rudjer Boskovic Institute |
| Citations | 21 |
Abstract
Section titled āAbstractāThe paper reports the micron-scale investigation of \nan all-carbon detector based on synthetic single crystal CVD-diamond \nhaving an array of cylindrical graphitic buried-contacts, \nabout 20 Ī¼m in diameter each, connected at the front side by superficial \ngraphitic strips. To induce diamond-to-graphite transformation \non both detector surface and bulk volume, direct-laserwriting \ntechnique was used. Laser-treatment parameters and cell \nshape have been chosen to minimize the overlapping of laser-induced \nstressed volumes. Optical microscopy with crossed polarizers \nhighlighted the presence of an optical anisotropy of the \ntreated material surrounding the embedded graphitized columns, \nand non-uniform stress in the buried zones being confirmed with \na confocal Raman spectroscopy mapping. Dark current-voltage \ncharacterization highlights the presence of a field-assisted detrapping \ntransport mainly related to highly-stresses regions surrounding \nburied columns, as well as superficial graphitized strips \nedges, where electric field strength is more intense, too. Notwithstanding \nthe strain and electronic-active defects, the detector \ndemonstrated a good charge collection produced by 3.0 and 4.5 \nMeV protons impinging the diamond, as well as those generated \nby MeV Ī²-particles emitted by 90Sr source. Indeed, the mapping \nof charge collection efficiency with Ion Beam Induced Charge \ntechnique displayed that only a few micrometers thick radial region \nsurrounding graphitic electrodes has a reduced efficiency, \nwhile most of the device volume preserves good detection properties with a charge collection efficiency around 90% at 60 V of biasing. \nMoreover, a charge collection efficiency of 96% was estimated \nunder MeV electrons irradiation, indicating the good detection \nactivity along the buried columns depth.