Vacancy-type defects created by single-shot and chain ion implantation of silicon

Abstract

Abstract. Vacancy-type defects created by single-energy implantation of Czochralski-grown single-crystal silicon by 4 MeV silicon ions at doses of 10 12 and 10 13 cm −2 have been compared with those created by an energy chain of implants of 0.4, 0.9, 1.5, 2.2 and 4 MeV ions, each at one-fifth of the singleenergy dose. Measurements were taken for as-implanted samples and after annealing to temperatures up to 600• C. In contrast to the expectation that a more uniform depth distribution of interstitials and vacancies would lead to a more efficient recombination and consequently fewer surviving vacancies, vacancyrelated damage survived in the chain-implanted samples to higher temperatures, before almost complete annealing at 600• C. It is therefore concluded that it is the absolute initial monovacancy concentration, rather than any initial separation of vacancy-and interstitial-rich regions, that determines the probability of survival as divacancies, and that there exists a threshold divacancy concentration of 1-2 × 10 18 cm −3 for clustering at 400-500

The Influence of Pico-Second Pulse Electron Irradiation on the Electrical-Physical Properties of Silicon Crystals

“…After irradiation there are two mechanisms for carrier scattering (line 2). The mathematical expression for the mentioned cases is as follows: µ~Т α , α 1 = −2.18 before irradiation and α defects [5]; in the given case, scattering on the radiation defects created by pico-second pulse irradiation with 3.5 MeV energy. Evidence for this statement is temperature dependencies of electrical conductivity and carrier mobility for different samples with specific resistivity of 100 Ω•cm, 700 Ω•cm, 950 Ω•cm (Figure 5 and Figure 6).…”

“…There are numerous publications devoted to the influence of irradiations, in particular high energy electron irradiation, on the properties of silicon crystal. One can present an extensive bibliography, however it is better to refer to reviews and monographs presenting more informative data about findings on this subject [1]- [5]. The irradiation sources used in these works are conventional sources based on micro-second pulse beams (accelerators, nuclear reactors and so on) allowing to accumulate a large amount of irradiation doses in a short time and, consequently, quickly affect properties of irradiated materials.…”