DEEP LEVEL TRANSIENT SPECTROSCOPY OF THE STRUCTURES DASED ON DIAMOND FILMS

摘要

The parameters of trapping centers in CVD diamond films before and after post deposition treatment surface by hydrogen and argon plasma and in diamond p-n junction were studied for the first time by new isothermal Charge-based Deep Level Transient Spectroscopy (Q-DLTS). The concentrations, activation energies, capture cross-sections and locations of the trapping centers were determined. The Q-DLTS showed that micro defects of the all samples with CVD diamond films and in diamond p-n junction are acting as trapping centers (point defects) and have the continuous energy spectrum with one or two maximums at different energies. It was found that as-deposited diamond surface were characterized by the high density of the surface point defects - electrical active trapping centers. A treatment of diamond surface with hydrogen plasma substantially decreased a density of defects. In the case of argon treated, the Ar plasma induced new point defects and changed their energy distribution. Deep levels with energies E_A ≈ 0.4 eV, E_D ≈ 0.8 eV and related capture cross-sections σ_A ≈ 10~(-14) cm~2, σ_D ≈ 10~(-14) cm~2 were obtained from Q-DLTS spectra of diamond p-n junction. Analysis of the Q-DLTS spectra measuring at different conditions was shown that parameters E_A, σ_A characterize point defects induced by boron in p-type CVD diamond film, and E_D, σ_D - induced by arsenic in n-type synthetic diamond crystal.