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HL: Halbleiterphysik
HL 3: Quantenpunkte und -dr
ähte: Herstellung und Charakterisierung
HL 3.6: Talk
Monday, March 8, 2004, 11:30–11:45, H17
Multi-Dot Floating-Gates in MOSFETS for Nonvolatile Memories - Their Ion Beam Synthesis and Morphology — •T. Müller1, K.-H. Heinig1, C. Bonafos2, H Coffin2, G. Ben Assayag2, S. Schramm2, G Zanchi2, A. Claverie2, M. Tence3, and C. Colliex3 — 1Forschungszentrum Rossendorf, Institut für Ionenstrahlphysik und Materialforschung, Dresden, Germany — 2CNRS/CEMES, Toulouse, France — 3Laboratoire de Physique des Solides, Universite Paris-Sud, Orsay, France
Scalability and performance of current FLASH memories could be improved substantially by novel devices based on Multi-Dot Floating Gate MOSFETS. Here, we present experimental and theoretical studies on the low-energy ion beam synthesis of narrow Si nanocrystal (NC) layers embedded in thin SiO2 films. NCs are produced by Si+ implantation into SiO2 and subsequent thermal treatment during which Si phase separates from the supersaturated SiO2. Till now, the study of the phase separation suffered from the weak mass contrast in TEM between the Si and SiO2 phases. In this contribution, we investigate the morphology of the Si quantum dot floating gate by Energy Filtered Scanning Transmission Electron Microscopy (EFSTEM). A comparison of the observed Si pattern with predictions of kinetic lattice Monte Carlo (MC) simulations has been performed. It was found that the morphology of the synthesized multi-dot Si floating gate changes with increasing ion fluence (Si concentration) from isolated, spherical NCs to percolated structures. The pattern of the phase separated Si predicted by kinetic Monte Carlo simulations and observed by Electron Microscopy agree remarkably well.