Photo-induced deep level analysis in undoped CVD diamond films

Abstract

Combined thermally stimulated currents (TSC) and photo-induced current transient spectroscopy (PICTS) have been carried out on undoped high quality chemical vapour deposition (CVD) diamond films. Cross analysis of the experimental data was performed in order to determine the characteristic parameters of the traps affecting the electrical transport processes. Measurements were performed in the temperature range from 120 to 650 K. The traps were excited by means of a pulsed Xenon lamp and a 20 MeV electron beam from a linear accelerator. Both PICTS, performed between room temperature and 650 K, and TSC, from 120 to 320 K, have shown two dominant peaks, simultaneously analysed to carry out a signature of the deep levels consistent with the two different measurements. The TSC analysis at high temperature has detected deep states from 0.95 to 1.3 eV. The concentration of traps of the dominant component at high temperature after 20 MeV electron exposure at a saturation dose of 10 Gy has been calculated from the integrated charge by a direct measurement of the charge collection efficiency of the samples and resulted in a value as high as 4×10 18 cm −3 .