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0978-GG16-02

Multiscale Modeling of Growth and Structure of Silicon Nanoparticles in an Oxide Matrix Decai Yu, Sangheon Lee, and Gyeong S Hwang Chemical Engineering, The University of Texas at Austin, 1 University Station C0400, Austin, TX, 78712 ABSTRACT A first principles-based multiscale model is developed to examine mechanisms underlying Si nanocrystal formation in Si-rich SiO2. Using the multiscale approach, we have found that the embedded nanocrystal formation is mainly driven by suboxide penalty arising from incomplete O coordination, with a minor contribution of strain, and it is primarily controlled by O diffusion rather than excess Si diffusion and agglomeration. The overall behavior of Si cluster growth from our Monte Carlo simulations based on these fundamental findings agrees well with experiments. INTRODUCTION With continued scaling, chip performance becomes increasingly limited by interconnect delay. In the long term, materials innovation alone will no longer satisfy the performance requirements due to the limited conductivity of present conductor materials. The quest for optical interconnects is motivated by physical limitations of the conventional conductor/dielectric system for chip-level global interconnects. Silicon is indirect gap materials, thereby yielding very low efficiency for luminescence. However, the discovery of efficient room temperature luminescence from oxide embedded Si nanocrystals led to the rapid evolution of silicon microphotonics. The absorption and luminescence properties of oxide embedded Si nanocrystals are mainly governed by: the size, shape, and spatial arrangement of Si nanocrystals; the atomic structure, bonding, and defects at nanocrystal-matrix interfaces; and the atomic structure and composition of oxide matrices. This suggests that the visible light emission from the oxide embedded Si nanocrystal system could originate from not only quantum confinement but also composition and bonding configuration at nanocrystal-matrix interfaces as well as in oxide matrices. Therefore, atomic scale control of the growth and structure of embedded nanocrystals will offer an enormous opportunity to accelerate the development of Si-based optoelectronic devices. However, even mechanisms underlying Si nanocrystal formation in a Si suboxide matrix are still uncertain. While conventional experimental techniques alone are limited to providing complementary atomic-level, real space information, first principles-based multiscale modeling, with proper experimental validation, can contribute greatly to elucidating the underlying growth mechanisms of embedded Si nanocrystals and their synthesis-structure-property relationships as well as improving existing (or developing new) process technologies. In this paper, we present a multiscale model for the growth and structure of oxide-embedded Si nanocrystals, based on various state-of-the-art theoretical techniques at different time and length scales including: first principles Quantum Mechanics (QM), Molecular Mechanics (MM), and Monte Carlo (MC).