GaN nanocrystals obtained by Ga and N implantations and thermal treatment under N2 into SiO2/Si and SiNx/Si wafers

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:485

Article

Aggar, L.^1,2  Bradai, D.¹  Bourezg, Y. I.^1,3  Abdesselam, M.^1,2  Chami, A. C.¹  Mocuta, C.⁴  Thiaudiere, D.⁴  Speisser, C.²  Muller, D.²  Bouillet, C.⁵  Le Normand, F.² 

[1] Univ Sci & Technol Houari Boumediene, Fac Phys, Algiers, Algeria

[2] Univ Strasbourg, CNRS, ICube, UMR, F-67037 Strasbourg, France

[3] Univ Ziane Achour, BP 3117, Djelfa 17000, Algeria

[4] Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France

[5] Univ Strasbourg, CNRS, IPCMS, UMR, F-67034 Strasbourg, France

关键词: GaN;    Ga-0;    Ga2O3;    SiO2;    SiNx;    RBS;    XPS;    TEM;    XRD;    XAFS;   

DOI  :  10.1016/j.nimb.2020.10.012

来源: Elsevier

【 摘 要 】

The formation of GaN nanocrystals in SiO2/Si and SiNx/Si dielectric layers implanted with Ga + and N + ions, followed by annealing at 950 degrees C for 60-120 min in N-2, has been studied by high resolution transmission electron microscopy (HRTEM), synchrotron radiation X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) technique at the Ga K-edge, as well as by Rutherford Backscattering spectrometry (RBS), X-Ray photoelectron spectroscopy (XPS), Raman spectroscopy (RS) and Scanning electron microscopy (SEM). The effect of the dielectric matrix, of the gas annealing environment (N-2) and of the annealing time at 950 degrees C have been inves-tigated. GaN nanocrystals implanted near the surface are observed in SiO2/Si only. The hexagonal wurtzite crystalline structure was confirmed by HRTEM, XRD and Raman spectroscopy. However, the synthesis process is multiphasic as elemental Ga-0 nanoparticles at larger depths and Ga2O3 rods (similar to 200-300 nm) on the surface were formed in addition to implanted h-GaN, as shown by TEM, XAFS, SEM, XPS and Raman spectroscopy. Moreover, Ga atoms are always remaining on some vacant Si sites in the SiO2 matrix. The local environment around Ga is quite different in the SiNx matrix, as seen by XAFS. This difference can be explained by the gallium and nitrogen diffusions which are much faster in the case of the SiO2 matrix, as shown by RBS profiles. Results are discussed in close comparison with existing literature.

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