Strain-induced modification of trap parameters due to the stopped ions in Bi-irradiated Si
National Institute of Materials Physics - 105bis Atomiştilor Street, 077125, Măgurele, Romania
Received: 22 July 2014
Accepted: 12 October 2014
By implanting Bi in Si, a strong strain field due to the bigger atomic mass and size of stopped Bi ions than Si lattice ones is produced, together with irradiation defects. The controlled doping of Si with Bi leads to modern applications such as quantum information processing. Here we show that the parameters of trapping centres are modified under the strain field. In the literature there are no reports on this subject. We irradiated Si wafers with ions of 28 MeV kinetic energy, 3° off axis orientation. The depth distributions of stopped ions and of primary defects were simulated. The traps produced by irradiation were investigated using the thermally stimulated currents method without bias. We recorded and modelled the discharge current curves. The strain field was modelled as a permanent and temperature-independent electric field. The traps of , , and and other two not assigned were evidenced. We have found that all trapping levels are broadened, and all capture cross-sections are temperature dependent which we attribute to the strong strain field produced by Bi. These results are important and must be taken into account in designing and manufacturing microelectronic devices incorporating strain, including the topical spin qubit ones.
PACS: 61.82.Fk – Semiconductors / 72.20.Jv – Charge carriers: generation, recombination, lifetime, and trapping / 61.80.Jh – Ion radiation effects
© EPLA, 2014