. Anatoli Korkin Nano & Giga Solutions Outline: Retrospection and Forecast Atomic Scale Materials Design A few steps from atoms to devices Future Research Software Development Anatoli Korkin Nano & Giga Solutions, Phoenix, Arizona Computational Design of Si/SiO 2 Interface for Advanced and Future Electronics . Anatoli Korkin Nano & Giga Solutions Conventional CMOS devices shrink to the nanoscale dimensions Source Drain < 100 nm < 10 nm New type of devices based on SiO 2 /Si interface are emerging Quantum dots Nano wires SiO 2 /Si Interface: Why atomic scale insight is needed . Anatoli Korkin Nano & Giga Solutions Materials chemistry at atomic scale Reactor Models Equipment Data Atomic Scale Deposition Models Atomic Scale Film & Device Models Deposition Rates, Film Uniformity: Reactor & Process Design temp, pressure concentrations Ab initio reaction rate constants, Mechanisms Process Data Material/Device Structure Data INPUTS MODELS Empirical reaction rate constants, Mechanisms tool geometries, flow rates dopants, anneal temp crystal type, grain boundary, interfaces, etc. OUTPUTS Film & Interface Structure & Stability: Process & Material Design Film & Interface structure Electric Properties & Reliability: Device Design . Anatoli Korkin Nano & Giga Solutions A snapshot of an interface formation An Integrated kMC-MD approach: DFT cluster & periodic study: reacting molecules and barriers Chemical kinetics calculations: elementary chemical reactions Kinetic Monte Carlo simulation: interface formation & film growth Molecular dynamic simulation: conformations & surface relaxation . Anatoli Korkin Nano & Giga Solutions Periodic Slab Cluster models of hydroxylated oxidized Si(100) surface Cluster I Cluster II Cluster & Periodic DFT Study . Anatoli Korkin Nano & Giga Solutions Adsorption complex Transition state Product E ( in kcal/mol ) SiCl 4 Adsorption on OH Terminated Si(100) Surface . Anatoli Korkin Nano & Giga Solutions REACTION PATH PROFILES X Y/s ==> Z W/s X=MCl 4 ; Y/s {Si}OH; Z HCl; W/s {Si}OMCl 3 ; M = Zr, Hf Kinetics of Gas-Surface Reactions . Anatoli Korkin Nano & Giga Solutions Graphic view Kinetic MC solver Summation rules, QEq scheme, neighbours search algorithm Tersoff correlation Potential library Ewald sum and optimal grid generator Molecular dynamics solver Molecular mechanics methods. A Scheme of the kMC-MD Program . Anatoli Korkin Nano & Giga Solutions Describes film growth in: 1.Physical Vapor Deposition (PVD) process 2.Molecular Beam Epitaxy (MBE) 3.Ion assisted deposition (IAD) methods 4.Chemical Vapor Deposition (CVD) 5.Ion implantation Can be used to study: 1.Film structure and roughness vs substrate temperature 2.Film structure and roughness vs energy of incident particles 3.Film structure and roughness vs lattice misfit 4.Stress relaxation in the film 5.Non-equilibrium dynamical processes during deposition Model of Film Growth from Molecular Blocks . Anatoli Korkin Nano & Giga Solutions Force Field potential O O O O H H H H H H ZrZr r Si . Anatoli Korkin Nano & Giga Solutions Fixed layer to maintain structure Layer connected with thermostat (velocity rescaling) Random position is selected over film surface. A molecule at random orientation with random velocity impinges on the surface Model Implementation . Anatoli Korkin Nano & Giga Solutions T = 1500 K, E = 3 eVT = 900 K, E = 3 eV Film Structure Dependence on the Substrate Temperature & Energy of Incident Particles Film Structure Dependence on the Substrate Temperature & Energy of Incident Particles T = 1500 K, E = 30 eV . Anatoli Korkin Nano & Giga Solutions 2D 3D Pasquarello et al., PRL, 74 (1995) 1024 N.Tit & M. Dharma-Wardana, JAP, 86 (1999) 1 Initial models of SiO 2 /Si(100) interface . Anatoli Korkin Nano & Giga Solutions O1O2O3O4 2D D in eV Relative energies of oxygen vacancies . Anatoli Korkin Nano & Giga Solutions 2D: D: BulkInterface E Centers + OH defects . Anatoli Korkin Nano & Giga Solutions Novel interface models. I. . Anatoli Korkin Nano & Giga Solutions (100)(111)(110) (d) (e)(f) Fig. 4 Novel interface models. II. . Anatoli Korkin Nano & Giga Solutions LatticeGGALDA {Si 50 O } {Si 66 O } {Si 60 O } {Si 52 O } {Si 68 O } {Si 52 O } m-n/2 {Si} + n/2{SiO 2 } {Si m O n } E (eV) I. Stress Energies at Si-SiO 2 Interfaces Dharma -Wardanas Extra layer of Si Less O at the interface Novel interfaces . Anatoli Korkin Nano & Giga Solutions Chemical: (Hamann, PRB, 2000) Si(+1)=0.47 Si(+2)=0.51 Si(+3)=0.24 II. Stress Energies at Si-SiO 2 Interfaces LatticeTOTALCHEM () {Si 50 O } (3.96) {Si 66 O } (4.84) {Si 60 O } (4.33) {Si 52 O } (3.98) {Si 68 O } (4.39) {Si 52 O } (2.90) Mechanical: Bond lengths and angles are not at optimal Polarization: Coulomb interactions . Anatoli Korkin Nano & Giga Solutions Elementary quantum dots: Si-in-SiO 2 and SiO 2 -in-Si +O: (0.94) +2O: 1.08 (1.45) +3O: 2.64 (1.65) +4O: 3.84 (1.88) -O: 1.84 (0.48) -2O: 3.13 (0.99) -3O: 4.94 (1.19) -4O: 5.14 (0.96) Total stress (chemical stress) Si dot in SiO 2 SiO 2 dot in Si . Anatoli Korkin Nano & Giga Solutions 1 nm Si wire in 2 nm SiO 2 box: Initial steps + . Anatoli Korkin Nano & Giga Solutions 1 nm Si wire in 2 nm SiO 2 box: Generic view . Anatoli Korkin Nano & Giga Solutions 1 nm Si dot in 2 nm SiO 2 box: clever (?) guess quartz: 3 x 3 x 3 Si (100): 2 x 2 x 2 a = b = c = = = = 90 o Si 243 O 401 Si - 42 SiO . Anatoli Korkin Nano & Giga Solutions 1 nm Si dot in 2 nm SiO 2 box . Anatoli Korkin Nano & Giga Solutions Si/SiO 2 /Si Gate Stack Model Total potential (eV) Leakage current (A/cm 2 ) L. Fonseca et al. . Anatoli Korkin Nano & Giga Solutions Model SiO 2 /Si/SiO 2 channel H-saturated Pb centers L. Fonseca et al. . Anatoli Korkin Nano & Giga Solutions Transport results for SiO 2 /Si/SiO 2 L. Fonseca et al. . Anatoli Korkin Nano & Giga Solutions KHIMERA: Kinetics from Molecules to Reactor ReactantTransition stateProductMinimum energy path Individual reaction rates Complex chemical kineticsChemistry in CVD reactor . Anatoli Korkin Nano & Giga Solutions Import of QC Results Viewing of the Molecular Structure Viewing of the Molecular Structure Summary of QC Results Initial Settings for Reaction Rates Calculation Initial Settings for Reaction Rates Calculation . Anatoli Korkin Nano & Giga Solutions Results of Thermochemical Calculations Results of Thermochemical Calculations Calculated Reaction Rates Graphical Representation of Results Graphical Representation of Results . Anatoli Korkin Nano & Giga Solutions Model, and process conditions Initial conditions and calculation details Initial conditions and calculation details Results . Anatoli Korkin Nano & Giga Solutions Pre-processor using GUI (with OpenGL based graphic engine) Solver (Fortran-90 modules) Post-processor using GUI SAGEMD: Atomic scaleaterials design . Anatoli Korkin Nano & Giga Solutions Structure Modification . Anatoli Korkin Nano & Giga Solutions Property Analysis . Anatoli Korkin Nano & Giga Solutions 1. Designed novel SiO 2 -Si interfaces with (111) and (110) surface termination comparable in the quality with SiO 2 -Si (100) 2. Incorporation of initial oxygen atom in Si demonstrates thermo- dynamic stabilization effect. Summary 1. Comparative study of SiO 2 -Si and other dielectric/semiconductor Interfaces for advanced and future electronics: SOI, novel devices, etc. 2. Comparative study of SiO 2 -Si interfaces in planar structures, wires, and quantum dots, e.g. 1D- vs 2D- vs 3D-nanostructures. Future plans . Anatoli Korkin Nano & Giga Solutions Co-authors: University of Florida: R. Barlett SEMATECH: G. Bersuker Tyndal National Institute, Ireland: J. Greer Collaboration: Brazil: L. Fonseca Japan: K. Yamashita Russia: A. Aleynikov, A. Knizhnik