Triode structure of ion detector based on 6H–SiC epitaxial films

Abstract

The possibility of the ≈10 2 times inner amplification of signals in SiC-based detectors of short-range ions was shown. Detector was realized by growth of p-type epilayers on base of 6H–n +-SiC substrate. Doping level in the films was 2.8×10 15 cm −3 , thickness ≈10 μm. Ni Schottky diodes were formed on films surface by magnetron sputtering. Final detector has n–p–n +-like structure. Detector parameters were investigated in regime of “floating base”. α-Particles from 244Cm with energy 5.8 MeV was used and investigated the increasing of the signal ( Q) with increasing applied voltage ( U). The superlinear growing of Q with significant (tens of times) amplification of the introduced by α-particle nonequilibrium charge was found. Irradiated structure was equal to phototriode which allows to use the results of Grinberg [Solid State Phys. 1 (1959) 31], obtained for transport of the introduced in base charge at δ-like voltage pulses on emitter–base junction. Using model from Grinberg [Solid State Phys. 1 (1959) 31], approximation of the experimental dependence Q( U) gives value for electron diffusion lengths in base of 5.9 μm.