Identification of nitrogen decorated vacancies in CVD diamond films using positron annihilation coincidence Doppler broadening spectroscopy

摘要

Positron annihilation studies were carried out to understand the defect structure in CVD diamond films. Defects in these films play an important role in determining their electrical, mechanical and optical properties. Positron annihilation two-detector coincidence Doppler broadening (CDB) technique was employed to identify and quantify the elements decorating these defects. A typical two-dimensional CBD spectrum is shown in Fig. 1. The higher momentum region of the CDB spectra, which is characteristic of a particular element was analyzed to obtain this information. The ratio of CDB spectrum of diamond film, graphite and silicon nitride to silicon were obtained to highlight the differences in the spectra as shown in Fig. 2.