Speaker
Mr
Daniel Silva
(Universidade do Porto)
Description
We have studied the lattice location of the transition metals 61Co (1.6 h) and 65Ni (2.5 h) in Si single crystals of various doping types by means of on-line Emission Channeling using Short-Lived Isotopes (IS453 EC-SLI). 65Ni was directly obtained by means of Ni RILIS ionization, while for the 61Co experiments we implanted the short-lived precursor isotope 61Mn(4.6 s) which decays via 61Fe (6 min) to 61Co, during the Mn RILIS run. In this case only measurements after a waiting period of 30 min were considered.
The samples were low-doped n-Si (7.3-12 Ohm cm, in the following named i-Si), as well as highly p+ (0.0053 Ohm cm) and n+ (0.0030 Ohm cm) doped Si.
While full quantitative analysis of the measured EC-SLI patterns by means of fitting to the results of manybeam simulations of emitter atoms on various lattice sites has not yet been performed, a qualitative inspection gave the following preliminary results.
Directly after room temperature implantation, the major lattice sites occupied by 61Co and 65Ni were substitutional or near-substitutional sites in all doping types studied.
However, after annealing at 500°C 65Ni changed to tetrahedral interstitial (T) sites in i-Si and p+-Si, while the majority of 65Ni in n+-Si was found on bond-centered (BC) interstitial sites after the same annealing temperature.
Site changes to interstitial T sites were also observed for 61Co in i-Si and p+-Si, while the case of 61Co in n+-Si is still waiting to be measured at next year's Mn beam time.
The behaviour of Co and Ni in Si shows hence some similarities to Fe in i-Si, where site changes from near-S to T sites were already observed in previous
experiments. However, there are also clear differences. While the site changes S->T in the case of Ni and Co occurred already after annealing at 475-500°C, in the case of Fe in i-Si around 600°C was required in order to promote the corresponding effect.
Also, while Fe showed considerable resistance against high-temperature annealing, which went along with the occupation of ideal substitutional sites after 900°C annealing, Co and Ni started to show partial out-diffusion from the samples already for annealing temperatures in the 600-850°C range.
Primary author
Mr
Daniel Silva
(Universidade do Porto)
Co-authors
Prof.
André Vantomme
(Inst. voor Kern- en Stralingsfysica - KU Leuven)
Mr
Eric Bosne
(Universidade do Aveiro)
Prof.
Joao Pedro Esteves De Araujo
(Universidade do Porto Laboratorio de Fisica)
Dr
João Guilherme Martins Correia
(Instituto Tecnológico e Nuclear Sacavém)
Mrs
Ligia Pinto De Almeida Amorim
(Inst. voor Kern- en Stralingsfysica - KU Leuven)
Mr
Lino Miguel Da Costa Pereira
(Inst. voor Kern- en Stralingsfysica - KU Leuven)
Prof.
Manuel Castro Ribeiro Da Silva
(Instituto Superior Tecnico IST)
Dr
Stefan Decoster
(Inst. voor Kern- en Stralingsfysica - KU Leuven)
Dr
Ulrich Wahl
(Instituto Tecnológico e Nuclear Sacavém)
