Competition between damage buildup and dynamic annealing in ion implantation into Ge

Abstract

Channeling implantation of Ga into Ge is performed at two very different ion fluxes (1012 and 1019cm−2s−1), at two temperatures (room temperature and 250°C), and at five different fluences. The fluence dependence of the range profiles and of the implantation damage is strongly influenced by defect accumulation and dynamic annealing. At 250°C, the maximum lifetime of the defects is less than 10s. On the other hand, at room temperature no significant annealing is found within the first 10s after ion impact. The measured Ga depth profiles are reproduced very well by atomistic computer simulations.

Effects of current on early stages of focused ion beam nano-machining

“…This means that for higher currents at low doses more amorphous layers are produced. Hence for the same energy deposited to the Si, the probability of sputtering is increasing, as in amorphous layers the displacement energy is lower compared to crystalline Si [22]. In this process the effect of temperature rise is negligible as it is less than 2 o C [24].…”

“…Where is the nominal ion flux; therefore, would be in the range of micro-seconds for used milling currents [22]. Therefore, the overlap of regions with defects produced by different ions is not probable with the studied currents.…”

The effects of dwell time on focused ion beam machining of silicon

“…For shorter dwell times a less amorphous substrate is created and dynamic annealing is applied to greater extent as the substrate is less damaged, when compared to longer dwell times. This would cause greater mobility of defects and diffusion of implanted Ga, leading to short range recombination such as Frenkel pair annihilation, as well as rearrangement of defect complexes within the region of a collision cascade [7].…”

“…It is important to note that the depth distribution of the implanted Ga ions is independent of the ion flux [7]. In the Sigmund model, the target temperature does not have any direct effect on sputtering yield [8].…”

Atomistic modeling of Ge damage accumulation, amorphization and solid phase epitaxial regrowth

“…The same occurs depending on the time of implantation. Even at high temperatures of implantation, if the flux is high enough, the generated damage will not have enough time to recombine, or heal, leading to amorphization in conditions for which at a standard flux, no damage at all will effectively be measured, Posselt et al (2006).…”