Lateral IBIC characterization of single crystal synthetic diamond detectors

TL;DR

This study uses lateral IBIC analysis with a proton microbeam to evaluate charge collection efficiency profiles in single-crystal synthetic diamond detectors, revealing insights into electric field distribution, doping, and carrier diffusion.

Contribution

It introduces a lateral IBIC method for detailed CCE profiling in diamond detectors, providing new insights into electric field and doping characteristics.

Findings

CCE reaches 100% in the depletion region

High efficiency region width depends on bias voltage

Diffusion length of minority carriers estimated from CCE profile

Abstract

In order to evaluate the charge collection efficiency (CCE) profile of single-crystal diamond devices based on a p type/intrinsic/metal configuration, a lateral Ion Beam Induced Charge (IBIC) analysis was performed over their cleaved cross sections using a 2 MeV proton microbeam. CCE profiles in the depth direction were extracted from the cross-sectional maps at variable bias voltage. IBIC spectra relevant to the depletion region extending beneath the frontal Schottky electrode show a 100% CCE, with a spectral resolution of about 1.5%. The dependence of the width of the high efficiency region from applied bias voltage allows the constant residual doping concentration of the active region to be evaluated. The region where the electric field is absent shows an exponentially decreasing CCE profile, from which it is possible to estimate the diffusion length of the minority carriers by means of a drift-diffusion model.