RBS Investigation of Ion Implanted SiSiO₂ Structures Irradiated with 20 MeV Electrons

Abstract

Summary: The influence of high‐energy electron irradiation on the redistribution of silicon and oxygen atoms in implanted SiSiO2 structures has been investigated by Rutherford backscattering spectroscopy (RBS). Two groups of SiSiO2 samples implanted with different doses of silicon ions (1 × 1012 cm−2 and 1 × 1016 cm−2) are used. The ion energy of 15 keV is chosen to produce maximum radiation defects at the SiSiO2 interface. The structures are then irradiated with 20 MeV electrons for different durations (from 60 s up to 120 min). After electron irradiation, the redistribution of the oxygen and silicon atoms in the samples implanted with 1 × 1012 cm−2 Si+ ions is negligible: significant redistribution of these atoms is found only in SiSiO2 samples implanted a with dose of 1016 cm−2. These results demonstrate that the structural changes at the silicon surface of implanted SiSiO2 samples, which take place after electron irradiation, depend more strongly on the implantation dose than on the electron dose irradiation.

Formation of Si nanocrystals in ion implanted Si-SiO2structures by MeV electron irradiation

“…We assume that the MeV electron irradiation breaks Si-O bonds and the free oxygen atomes move through radiation defects, so that Si nanostructures are generated in the SiO 2 . This is in good agreement with our earlier results [7][8][9] where we showed that oxygen accumulates at the SiO 2 -Si interface. We also assume that the radiation defects (created by the MeV electron irradiation) act as a source for Si nanostructures generation in the SiO 2 .…”

“…As after electron irradiation both (oxygen and silicon) peaks of the RBS/C spectra widen in the same way, it can be assumed that the electron irradiation generates additional radiation defects, which are the reason for the radiation- 5 To whom any correspondence should be addressed. enhanced diffusion of oxygen and an insignificant increase of the amorphous Si layer depth [9]. We compare here these results with AFM measurement of the same samples.…”

“…Using RBS/C spectra, it has previously been shown that the silicon and oxygen concentrations before and after high-energy electron irradiation are different [9]. As after electron irradiation both (oxygen and silicon) peaks of the RBS/C spectra widen in the same way, it can be assumed that the electron irradiation generates additional radiation defects, which are the reason for the radiation- 5 To whom any correspondence should be addressed.…”

MeV Electron Irradiation of Ion-Implanted Si-SiO2 Structures

“…But the substantial energy deposited cannot significantly promote the amorphization process of the silicon wafer. In this case, the results show that the amorphization process depends more effectively on the Si implantation dose than on the electron irradiation dose [3]. The spectra reveal four peaks (at 120, 160, 195, and 260 K) corresponding to four kinds of energy states located at the Si-SiO 2 interface.…”