Retention and re-emission behavior of hydrogen isotopes in SiC

Abstract

The retention and re-emission behaviors of hydrogen isotopes in SiC have been studied by means of the elastic recoil detection (ERD) technique. Protium ions or deuterium ions were implanted into SiC sample at room temperature up to almost saturation. It was found that the concentrations of protium and deuterium in SiC reach values of 0.70 and 0.75, respectively. The ratio of the saturation concentration of H to D is calculated to be 0.92 by the solution of the mass balance equations, which is consistent with the experimental value of 0.93.Isochronal annealing for 10 min from room temperature to 1123 K was applied to deuterium implanted SiC sample to analyze the thermal release behavior. It was found that the deuterium re-emission takes place in three stages. The major second and third stages are ascribed to the re-emission as deuterium molecule of deuterium atoms bound to Si and C in SiC, respectively. The first stage might be the re-emission of deuterium-silicon compounds such as SiD2 or SiD4. Isothermal annealing at 573 K and 773 K were applied to evaluate the amounts of deuterium re-emitted in the first and second stages. The mass balance equations were also used to evaluate the effective molecular recombination rate constant, which was determined to be 7.3 × 10-5.