Study of charge collection efficiency in 4H-SiC Schottky diodes with 12C ions

The Charge Collection Efficiency (CCE) in 4H-SiC epitaxial Schottky diodes is studied as a function of the applied reverse bias. Three SiC types, with different doping concentrations, were used to detect 12C ions at 14.2, 28.1 and 37.6 MeV. In two SiC types we observe minority charge carriers, generated by the incoming ion in the neutral region, which diffuse to the depleted layer and are finally collected. The minority carriers contribution to the CCE is well reproduced by an analytical equation which represents the contribution from the charge carriers diffusing to the depletion region from the semiconductor substrate. From a best fit procedure, the minority carriers diffusion length is extracted and the minority carriers lifetime is calculated. Finally, the dependence of the lifetime on the doping concentration is investigated.