Ultra-slow dynamic annealing of neutron-induced defects in n-type silicon: role of charge carriers
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Ultra-slow dynamic annealing of neutron-induced defects in n-type silicon: role of charge carriers Ying Zhang1,2 , Yang Liu1,2 , Hang Zhou1,2 , Ping Yang1,2 , Jie Zhao1,2 , Yu Song1,2,3,a 1 Microsystem and Terahertz Research Center, China Academy of Engineering Physics, Chengdu 610200,
China
2 Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621999, China 3 Present Address: College of Physics and Electronic Information Engineering, Neijiang Normal
University, Neijiang 641112, China Received: 22 June 2020 / Accepted: 8 October 2020 © Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Neutron bombardments with equivalent fluence (1 × 1010 cm−2 ) and different fluxes (2.5 × 105 cm−2 s−1 to 1 × 107 cm−2 s−1 ) have been performed on three kinds of bipolar devices with n-type silicon as active regions. The measured increase of base currents and input bias currents are found to decrease with increasing neutron flux, implying that the strength of the dynamic annealing of divacancy defects in n-type silicon follows a positive flux dependence. Such a flux dependence is the same as that observed in ions implantation using protons, but the evident flux sensitivity in our experiment is 4 orders of magnitude lower than that of proton bombardment, despite the similarity in the masses and energies of the two particles. The huge discrepancy of flux range is attributed to the presence of vast charge carriers in proton bombardments, which strongly accelerate the dynamic annealing of defects by enhancing the diffusion velocity of Si interstitials and dissociation rate of defect clusters. Our work would contribute to the understanding of the defect annealing processes in silicon.
1 Introduction Bombardment of energetic particles induces atomic displacements and structural defects in crystalline semiconductors. The population of the created stable defects depends on the process of the defects’ generation as well as their dynamic and thermal annealing during the bombardments. The dynamic annealing involves migration, recombination, and clustering of mobile point defects during irradiation [1, 2]. Factors of crucial importance for damage buildup in semiconductors are the energy, mass, fluence, and flux of the incident particles, as well as the temperature of the samples. Interestingly, the dependence of dynamic annealing on the fluence and flux shows non-trivial characteristics. For the experiments of total fluence exceeding 1 × 1012 cm−2 and flux in the range of 1 × 1010 –1 × 1015 cm−2 s−1 , it is well recognized that the strength of the dynamic annealing of defects decreases with increasing flux [3–8]. On the other hand, for the experiments of low total fluence of about 5 × 109 cm−2 and low flux in the range of 1 × 107 –2 × 1010 cm−2 s−1 , a reverse positive flux dependence of
a e-mail: [email protected] (corresponding author)
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Eur. Phys. J. Plus
(2020) 135:827
dynamic annealing is found in silic
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