Morphological, structural and luminescence properties of Si/β-FeSi₂/Si heterostructures fabricated by Fe ion implantation and Si MBE

Abstract

The morphology and optical properties of Si samples implanted by low-energy Fe+ ions with different fluences (1 × 1015–1.8 × 1017 cm−2) and further subjected to pulsed ion-beam treatment (PIBT) have been studied by atomic force microscopy and optical reflectance spectroscopy. It was proved that iron disilicide (β-FeSi2) crystallites were formed on the surface of the Si substrate as a result of ion implantation and PIBT. The method of ultrahigh vacuum and low-temperature (T = 850 °C) cleaning of Fe+-implanted Si samples has been applied for the first time. It was found that it is possible to form smooth epitaxial Si films with both a thickness of up to 1.7 µm and a reconstructed surface by molecular beam epitaxy on the surface of Si samples implanted with a fluence of up to 1 × 1016 cm−2. Further increase in the implantation fluence results in the disruption of epitaxial Si growth and to a strong increase in surface relief roughness due to 3D silicon growth mechanism. Preservation of β-FeSi2 precipitates inside the Si matrix after the formation of a cap epitaxial Si layer has been confirmed by optical spectroscopy data. Low temperature photoluminescence measurements in the range 1400–1700 nm showed that light emission of the formed Si/β-FeSi2/Si heterostructures is due to contributions from β-FeSi2 precipitates and dislocations.

Formation of Si-based light-emitting structures by ion implantation and pulsed treatments

“…The deconvolution of this band into three Gaussian components allowed us to reveal PL subbands peaked at 0.785, 0.81 and 0.855 eV which are in good agreement with the PL band energies originating from the -FeSi 2 precipitates and dislocations (D1-D2 lines) [11]. Thus, the pulsed treatments of the implanted Si layers allowed us to produce Si:Er and -FeSi 2 layers with the controlled dopant distribution, high crystal quality and intense light emission.…”

“…It is necessary to note that there is a limited number of publications concerning the creation of Si:Er andFeSi 2 layers by pulsed treatments [3][4][5][6][7]. Our group deals with 978-1-4244-3815-0/09/$25.00 ©IEEE the formation of Si-based light-emitting layers ( -SiC, -FeSi 2 , Si:Er) by ion implantation and pulsed treatments for ten years [8][9][10][11][12]. In this paper, the recent results for the formation of Si:Er and -FeSi 2 layers under the pulsed treatments are reviewed.…”