Roberto Flammini 1, Paolo Allegrini 2, Alessandro Bellucci2 , Frédéric Wiame 3, Rachid Belkhou4, Polina Sheverdyaeva5, Paolo Moras 5, Mahdi Hajlaoui 4, Fausto Sirotti 4, Stefano Colonna 1, Fabio Ronci 1 and Francesco Filippone2 1 CNR-ISM, Istituto di Struttura della Materia, Area della Ricerca di Roma Tor Vergata, Via Fosso del Cavaliere, 100 - 00100 Roma, Italia 2 CNR-ISM, Istituto di Struttura della Materia, UOS di Montelibretti, Via Salaria km 29.300 - 00016 Monterotondo Scalo (Roma), Italia 3 CNRS - Chimie ParisTech, Institut de Recherche de Chimie Paris, 11 rue Pierre et Marie Curie, 75005 Paris, France 4 Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, B.P. 48 F, F-91192 Gif Sur Yvette, France 5 CNR-ISM, Istituto di Struttura della Materia, Unità Staccata di Trieste, Area Science Park, S.S. 14, Km. 163,5, I-34012 Basovizza (TS), Italia Evidence for a surface state on the ?-Si3N4 (0001)-8x8 thin film grown on Si(111) Silicon nitride is a widely used material in electronics [1]. In the devices the interface between silicon nitride and other materials is not abrupt, being the nitride buffer layer amorphous and then source of defects. However, silicon nitride shows the remarkable property to grow epitaxially on Si(111), owing to a negligible lattice mismatch (<1.2% between the ?- Si3N4 (0001) surface and the 2x2 cell of the Si(111) plane) [2,3]. Although much effort has been devoted to the study of the ?- structural phase of the silicon nitride, a full understanding of the 8x8 surface reconstruction [3,5] and of the chemical bonds at the interface [2, 4, 6] has not been achieved so far. This is of paramount importance as the presence of surface and interface dangling bonds (DBs) induces gap states across the Fermi level, creating tunnelling channels which can reduce the performance of electronic devices. We report on measurements carried out by ARPES (Angle Resolved Photo Emission Spectroscopy), PES (Photoemission Spectroscopy), LEED (Low Energy Electron Diffraction) and STM (Scanning Tunneling Microscopy) as well as DFT calculations. In particular, ARPES spectra, showing the electronic structure of the system along the high symmetry directions, demonstrate the presence of a new band with a surface character likely attributed to the 8x8 reconstruction of the nitride layer. [1] V.I. Belyi et al. Silicon nitride in electronics, Vol. 34, Materials Science Monographs, Elsevier, Amsterdam (1988) [2] J. W. Kim et al PRB 67 (2003) 035304 [3] X.-S Wang et al. Surf Sci 494 (2001) 83, PRB 60 (2000) R2146 [4] Gwo et al. PRL 90 (2003) 185506; R. Flammini et al. Surf. Sci. 579, (2005) 188, J. Appl. Phys. 103, (2008) 083528, Surf. Sci. 606 (2012) 1215, K. Eguchi PRB 85 (2012) 174415 [5] H. Ahn et al. Phys. Rev. Lett. 86, (2001) 2818, C. L. Wu et al. PRB 65 (2002) 045309 [6] M. Yang et al. J. Appl. Phys. 105 (2009) 024108
Evidence for a surface state on the beta-Si3N4(0001)-8x8 thin film grown on Si(111)
R Flammini
2014
Abstract
Roberto Flammini 1, Paolo Allegrini 2, Alessandro Bellucci2 , Frédéric Wiame 3, Rachid Belkhou4, Polina Sheverdyaeva5, Paolo Moras 5, Mahdi Hajlaoui 4, Fausto Sirotti 4, Stefano Colonna 1, Fabio Ronci 1 and Francesco Filippone2 1 CNR-ISM, Istituto di Struttura della Materia, Area della Ricerca di Roma Tor Vergata, Via Fosso del Cavaliere, 100 - 00100 Roma, Italia 2 CNR-ISM, Istituto di Struttura della Materia, UOS di Montelibretti, Via Salaria km 29.300 - 00016 Monterotondo Scalo (Roma), Italia 3 CNRS - Chimie ParisTech, Institut de Recherche de Chimie Paris, 11 rue Pierre et Marie Curie, 75005 Paris, France 4 Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, B.P. 48 F, F-91192 Gif Sur Yvette, France 5 CNR-ISM, Istituto di Struttura della Materia, Unità Staccata di Trieste, Area Science Park, S.S. 14, Km. 163,5, I-34012 Basovizza (TS), Italia Evidence for a surface state on the ?-Si3N4 (0001)-8x8 thin film grown on Si(111) Silicon nitride is a widely used material in electronics [1]. In the devices the interface between silicon nitride and other materials is not abrupt, being the nitride buffer layer amorphous and then source of defects. However, silicon nitride shows the remarkable property to grow epitaxially on Si(111), owing to a negligible lattice mismatch (<1.2% between the ?- Si3N4 (0001) surface and the 2x2 cell of the Si(111) plane) [2,3]. Although much effort has been devoted to the study of the ?- structural phase of the silicon nitride, a full understanding of the 8x8 surface reconstruction [3,5] and of the chemical bonds at the interface [2, 4, 6] has not been achieved so far. This is of paramount importance as the presence of surface and interface dangling bonds (DBs) induces gap states across the Fermi level, creating tunnelling channels which can reduce the performance of electronic devices. We report on measurements carried out by ARPES (Angle Resolved Photo Emission Spectroscopy), PES (Photoemission Spectroscopy), LEED (Low Energy Electron Diffraction) and STM (Scanning Tunneling Microscopy) as well as DFT calculations. In particular, ARPES spectra, showing the electronic structure of the system along the high symmetry directions, demonstrate the presence of a new band with a surface character likely attributed to the 8x8 reconstruction of the nitride layer. [1] V.I. Belyi et al. Silicon nitride in electronics, Vol. 34, Materials Science Monographs, Elsevier, Amsterdam (1988) [2] J. W. Kim et al PRB 67 (2003) 035304 [3] X.-S Wang et al. Surf Sci 494 (2001) 83, PRB 60 (2000) R2146 [4] Gwo et al. PRL 90 (2003) 185506; R. Flammini et al. Surf. Sci. 579, (2005) 188, J. Appl. Phys. 103, (2008) 083528, Surf. Sci. 606 (2012) 1215, K. Eguchi PRB 85 (2012) 174415 [5] H. Ahn et al. Phys. Rev. Lett. 86, (2001) 2818, C. L. Wu et al. PRB 65 (2002) 045309 [6] M. Yang et al. J. Appl. Phys. 105 (2009) 024108I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.