Effect of the Fermi level position on the annealing characteristic of interstitial carbon defect in silicon

We present experimental results showing that the migration ability of interstitial carbon atom (Сi) in silicon depends noticeably on its charge state. The experimental results were obtained from the analysis of deep level transient spectra in n+–p diodes subjected to irradiation with 4–6 MeV electrons or α-particles at T < 273 k and subsequent heat-treatments in the temperature range 280–330 k under reverse bias and without it. It has been found that in the positive charge state the Сi migration energy is 0.88 ± 0.02 eV, while in the neutral charge state it is lowered down to 0.73–0.74 eV.

Behavior of nitrogen-related luminescence centers in laser-cut single-crystalline diamond under irradiation with keV electron beam

ABSTRACTWe have found that several nitrogen-related luminescence centers appear at 389 nm, 503 nm (H3 center), 575 nm (NV0 center), 637 nm (NV- center) in single-crystalline Ib diamond cut by means of a YAG laser irradiation process, followed by a suitable hydrogen microwave-plasma treatment, and that cathodoluminescence peaks related to these centers substantially change in intensity by irradiating the sample with 15-keV electron beam (EB). The relative number of 389-nm centers originating from a pair of a substitutional nitrogen atom and an adjacent interstitial carbon atom increased while the concentrations of the vacancy-related centers were reduced with increasing 15-keV EB doses. These facts indicate that both the process-induced self-interstitials and the vacancies in the diamond rather easily moved to more preferential positions to form their stabler defect states, being suggestive of possibility to control densities of NV and NV-related centers.

Interstitial Carbon Related Defects in Low-Temperature Irradiated Si: FTIR and DLTS Studies

The evolution of radiation-induced carbon-related defects in low temperature irradiated oxygen containing silicon has been studied by means of Fourier transform infrared absorption spectroscopy (FTIR) and deep level transient spectroscopy (DLTS). FTIR measurements have shown that annealing of interstitial carbon atom Ci, occurring in the temperature interval 260-300 K, results in a gradual appearance of a number of new absorption bands along with the well known bands related to the CiOi complex. The new bands are positioned at 812, 910.2, 942.6, 967.4 and 1086 cm-1. It has been found that the pair of bands at 910 and 942 cm-1 as well as another set of the bands at 812, 967.4 and 1086 cm-1 display identical behavior upon isochronal annealing, i.e. the bands in both groups appear and disappear simultaneously. The disappearance of the first group occurs at T = 285-300 K while the second group anneals out at T = 310-340 K. These processes are accompanied by an increase in intensity of the bands related to CiOi. It is suggested that intermediate states (precursors) are formed upon the transformation from a single (isolated) Ci atom to a stable CiOi defect. The results obtained in DLTS studies are in agreement with the FTIR data and show unambiguously the formation of CiOi precursors with slightly lower activation energy for the hole emission as compare to that for the main CiOi state.