Superdiffusion in Si Crystal Lattice Irradiated by Soft X-Rays

Abstract

We considered the reasons of superdiffusivity and measured profiles of boron and phosphorus in crystalline silicon at room temperature. The superdiffusivity or ultrafast diffusion of metastable vacancies at room temperature in Si crystal irradiated by soft X-rays was obtained experimentally. In this work, we presented experimentally obtained diffusion coefficients of singly and doubly negatively charged long-lived excited vacancies. These high concentration charged metastable vacancies (about 10 13 cm −3 ) at room temperature can very fast diffuse changing electrical conductivity and the Hall mobility of carriers. We measured the superdiffusivity of negatively charged vacancies, generated by the Auger effect in the regions of the sample, which were not affected by X-rays. In this paper, we presented the obtained superdiffusion profiles of boron and phosphorus in crystalline silicon measured with secondary-ion mass spectrometer.

Superdiffusion of Carbon by Vacancies Irradiated with Soft X-Rays in CZ Silicon / Superdifūzija Ar Vakancēm Iestarota Ar Mīkstajiem Rentgenstariem CZ Silīcijā

“…for density increase of carbon atoms in CZ silicon samples of d thickness of orientation > < 100 by superdiffusion [5], [11] we can find its penetration depths i x 0 for diffusion time t and coefficient…”

“…1, it is interesting to note that complexes VO 2 presented at band 886 cm 1 − , where there is no significant difference [17] from 889 cm 1 − , can be explained by irradiation influence on crystal lattice [4]. These mobile complexes play an important role in superdiffusion of the impurities [5] or in this case of carbon atoms at room temperature. These complexes can be produced by interstitial oxygen reactions with vacancies generated by the Auger effect [8].…”

“…Calculating absorption coefficients from transmittances presented in Fig. 1 for the peak at 1107 cm 1 − for interstitial oxygen i O and phonons 2TO+TA with absorption coefficient [6] at 1118 cm 1 − , we have obtained (10) From these coefficients and calibration factor [7] O σ = 3.14 ×10 17 cm -2 , we have obtained interstitial oxygen i O concentrations of irradiated samples for different anode voltages of 10, 20, 30 kV, consequently, (11) and for the non-irradiated sample (12) which is significantly less. We have measured the concentrations of interstitial oxygen i O and substitutional carbon S C using [17] well-known absorption bands at 1107cm 1 − and 605cm 1 − respectively.…”

“…For example, some properties of the charged vacancies and vacancies-oxygen complexes VO in crystalline silicon [1]- [4] can be investigated by measuring electrical conductivity [3], Hall mobility and lattice relaxations [4]. Superdiffusion of vacancies [2] irradiated by soft X-rays at room temperature and phosphorus and boron [5] have been investigated. Here we provide the analysis of superdiffusion of carbon from layer growth by vacuum evaporation on the surface [100] of silicon irradiated by soft X-rays.…”

“…Here we provide the analysis of superdiffusion of carbon from layer growth by vacuum evaporation on the surface [100] of silicon irradiated by soft X-rays. Fourier transform infrared (FTIR) spectroscopy has been used like powerful and sensitive technique to analyse the introduction of impurities into Czochralski silicon by point defects generated by irradiation with fast electrons [6], neutrons [7] as well as soft X-rays [5].…”