Lattice location of implanted Ag in Si

Abstract

The lattice location of implanted silver in Si was studied by means of the emission channeling technique. Following 60 keV room temperature implantation of radioactive 111 Ag at a dose of 2-3×10 12 cm −2 , we identify around 30% of Ag on near-substitutional sites (≈0.45 Å from ideal S-sites). Upon annealing at 200-300°C, the fraction on near-S sites reaches a maximum around 60-80%. For higher annealing temperatures it decreases again and at 600°C Ag starts to diffuse out of the Si samples. We estimate the activation energy for the dissociation of near-substitutional Ag to be 1.8-2.2 eV. The experimental results are compared to those of Cu in Si, and common features and characteristic differences in the behavior of the two group 1B metals are discussed. [4,5] and infrared absorption spectroscopy [6] to a defect of C 2v or lower symmetry, and was suggested to be neutral substitutional Ag S 0 . Electron paramagnetic resonance (EPR) measurements have identified at least 8 different Ag-related centers in Si, six of them are supposed to be due to pairs of Ag with other impurities or with itself [7][8][9]. Two centers, however, named NL56 and NL42 have been suggested to consist of substitutional Ag S 0 and tetrahedral interstitial Ag i 0 , respectively. While the NL56 center exhibited tetragonal (C 2v ) or lower symmetry, indicating a displaced substitutional position of Ag, the NL42 center was the only one found to have tetrahedral (T d ) symmetry.It is well known that Ag, like other transition metals, is gettered by highly damaged regions [10,11]

Lattice location and thermal stability of implanted nickel in silicon studied by on-line emission channeling

“…On their way out of the crystal, β − particles experience channeling effects along low-index crystallographic directions, depending on the lattice site occupied by the probe atom. EC has been used to study the lattice sites of long-lived TM isotopes in Si, such as 67 Cu (t 1/2 =2 d), 14-17 59 Fe (45 d) [17][18][19] and 111 Ag (7.45 d), 20 by means of off-line experiments. Studies of other TMs, in particular Ni, Co and Mn, were not feasible since the only suitable isotopes were too short-lived in order to be used off-line.…”

Study of thermal recrystallisation in Si implanted by 0.4‐MeV heavy ions

“…The recovery and removing of crystalline defects induced by the ion implantation in Si crystalline structure could be performed by thermal annealing at temperatures of 200°C to 600°C as was reported in Seo et al and Wahl et al 8,12 The annealing of the Si layers implanted with Ag (nano-composites of Ag particles were fabricated by 50-kV ion implantation using a high-beam current metal vapour vacuum arc ion source) at 400°C to 600°C leads to outdiffusion of Ag to the Si surface 8 or a significant decrease of the Ag content in the implanted layer (using 60-keV Ag) because of evaporation. 12 Ag impurity diffusion into the sample volume during heating, which also decreases the concentration of the implanted ions in the buried layer, was observed in Stepanov. 13 Point defects can agglomerate and form extended defect clusters of Si interstitials and clusters of vacancies and cavities, which require annealing temperatures of 800°C to 1000°C to be removed.…”

Воздействие импульсного лазерного излучения на слои Si с высокой дозой имплантированных ионов Ag-=SUP=-+-=/SUP=-

“…Однако для имплантированных слоев Ag : Si, подвергнутых термическому отжигу при T = 400−500 • С, наблюдалось вытеснение примеси Ag к поверхности [12,13], а при дальнейшем росте температуры отжига происходило испарение Ag из образцов [5]. Испарение Ag наблюдалось и в слоях Si, имплантированных низкой дозой ионов Ag + (D ∼ 10 12 ion/cm 2 ) [14]. При этом наряду с испарением возможна диффузия внедренной примеси Ag вглубь образца, что также понижает ее поверхностное содержание.…”