Oxygen-vacancy defects in electron-irradiated Si: the role of carbon in their behavior

Abstract

This is a detailed study of the effect of carbon impurity on the production of the oxygenvacancy (VO) pair and its conversion to the VO 2 defect, in electron-irradiated Czochralski silicon (Cz-Si) material, by means of infrared spectroscopy. Upon irradiation vacancies are trapped by oxygen atoms to form VO pairs and it was determined that the presence of carbon enhances the production of this pair. This is attributed to the tendency of carbon to capture self-interstitials, thus decreasing the annihilation rate between vacancies and self-interstitials produced during the irradiation and therefore increasing the availability of vacancies to pair with oxygen atoms in the course of irradiation. Upon annealing a number of VO pairs are captured by oxygen atoms to form VO 2 defects. It was determined that the percentage of the VO converted to the VO 2 defects decreases as the concentration of carbon increases. The phenomenon is discussed in terms of the various reaction channels that VO pair participates upon annealing and how the presence of carbon impacts the balance between these reactions, affecting the final products of the involved processes. Finally, an opposite trend for the conversion of the VO 2 to the VO 3 defect was observed. The percentage of VO 2 converted to VO 3 is enhanced with the increase of carbon content. This finding is discussed in terms of the effect of carbon in the oxygen diffusivity and the final impact on the reaction VO 2 + O i → VO 3 .2

Oxygen diffusion in germanium: interconnecting point defect parameters with bulk properties

“…These issues are more pronounced in the isostructural Si where O is introduced at high concentrations mainly due to the Czochralski. In Si, O interacts with carbon (C) or vacancies forming numerous defect complexes that impact device properties [20][21][22].…”

Comparative Study of Oxygen- and Carbon-Related Defects in Electron Irradiated Cz–Si Doped with Isovalent Impurities

“…When C s is present in the lattice, it competes with vacancies in capturing Si I (C s + Si I C i ) and this leads to a decrease in the rate of the annihilation reaction. In other words, the availability of V increases, allowing the possibility for more vacancies to be captured by O atoms [44]. Equivalently, VO production is increased (compare the C L and C H samples in Figure 3).…”

“…In the presence of C, there are three main reactions that take place in the Si lattice in the course of irradiation: V + Si I Ø (annihilation), V + O VO, and C s + Si I C i . The tendency of C to trap Si I 's leads to a decrease in the rate of annihilation of V, which enhances [44] the number of available V to be captured by O atoms. In other words, the formation of VO defects is enhanced.…”

“…In the course of irradiation, the produced Si I 's are readily captured by substitutional C s impurities. As a result, the C s atoms switch at interstitial sites, by the Watkins replacement mechanism [42], and the produced C i atoms react with other impurities, giving rise to the production of numerous defects complexes as mentioned above [16][17][18][19][20][21][22][23][24][25], and providing possibilities to elucidate the mechanisms of various defect reactions especially those involving oxygen impurities [43,44]. C as a codopant also affects the diffusion of various dopants such as, for example, B and P in Si [45][46][47], and suppresses crystal defects in Si-based structures and generally in other semiconductors [48,49].…”

Vacancy-oxygen defects in silicon: the impact of isovalent doping

“…The formation of CV pairs has been investigated [149][150][151][152][153] both experimentally and theoretically in the literature but there is no definite conclusion about their existence. Carbon also affects the production and evolution of vacancy-oxygen defects in irradiated Si [154][155][156]. It affects oxygen aggregation processes in Si in general, suppressing the thermal donor formation and enhancing oxygen precipitation, although the overall effect depends on the temperature range of the thermal treatments [157][158][159].…”