Diamond Detector With Laser-Formed Buried Graphitic Electrodes: Micron-Scale Mapping of Stress and Charge Collection Efficiency

Salvatori, Stefano; Jakšić, M.; Rossi, Maria Cristina; Conte, Gennaro; Kononenko, Taras; Komlenok, Maxim; Khomich, Andrey; Ralchenko, Victor; Konov, Vitaly; Provatas, G. (2019) Diamond Detector With Laser-Formed Buried Graphitic Electrodes: Micron-Scale Mapping of Stress and Charge Collection Efficiency. IEEE Sensors Journal, 19 (24). pp. 11908-11917. ISSN 1530-437X

Preview

PDF - Accepted Version - article
Download (14MB) | Preview

Official URL: http://doi.org/10.1109/JSEN.2019.2939618

Abstract

The paper reports the micron-scale investigation of an all-carbon detector based on synthetic single crystal CVD-diamond having an array of cylindrical graphitic buried-contacts, about 20 μm in diameter each, connected at the front side by superficial graphitic strips. To induce diamond-to-graphite transformation on both detector surface and bulk volume, direct-laserwriting technique was used. Laser-treatment parameters and cell shape have been chosen to minimize the overlapping of laser-induced stressed volumes. Optical microscopy with crossed polarizers highlighted the presence of an optical anisotropy of the treated material surrounding the embedded graphitized columns, and non-uniform stress in the buried zones being confirmed with a confocal Raman spectroscopy mapping. Dark current-voltage characterization highlights the presence of a field-assisted detrapping transport mainly related to highly-stresses regions surrounding buried columns, as well as superficial graphitized strips edges, where electric field strength is more intense, too. Notwithstanding the strain and electronic-active defects, the detector demonstrated a good charge collection produced by 3.0 and 4.5 MeV protons impinging the diamond, as well as those generated by MeV β-particles emitted by 90Sr source. Indeed, the mapping of charge collection efficiency with Ion Beam Induced Charge technique displayed that only a few micrometers thick radial region surrounding graphitic electrodes has a reduced efficiency, while most of the device volume preserves good detection properties with a charge collection efficiency around 90% at 60 V of biasing. Moreover, a charge collection efficiency of 96% was estimated under MeV electrons irradiation, indicating the good detection activity along the buried columns depth.

Item Type:

Article

Additional Information:

This work was supported in part by the Russian Ministry of Education and Science under Project 3.2608.2017/4.6, and in part by the Measurements at RBI have had the support of project AIDA-2020, under Grant 654168.

Uncontrolled Keywords:

3D detectors; β-particles; graphitic pillars; IBIC; protons; sc-CVD diamond

Subjects:

NATURAL SCIENCES
NATURAL SCIENCES > Physics

Divisions:

Division of Experimental Physics

Projects: