By Global TCAD Solutions (GTS)
A Cutting-Edge Quantum-Electronic Simulator GTS VSP (Vienna Schrödinger-Poisson) is a general-purpose quantum device simulator for arbitrary nano-structures, operating on the Schrödinger-Poisson equation system. VSP includes quantum mechanical solvers for closed-boundary and open-boundary problems; VSP is the first commercial solver to simulate quantum effects using physical models based on material properties, rather than relying on empirical models and parameters. The closed boundary model setup allows to calculate the quantum states or subbands as well as the self-consistent carrier concentration in FinFETs or nanowire cross-sections including confinement effects. The Schrödinger-Poisson system is solved on arbitrary one, two and three-dimensional geometries using tetrahedral and triangular meshes. The Schrödinger solver supports effective mass (EM) and k⋅p Hamiltonians that respond to arbitrary stress/strain distributions in the device. The Hamiltonians are automatically rotated to account for arbitrary substrate and channel orientations. Hetero-structured semiconductor devices, like resonant tunneling diodes (RTD) and quantum cascade lasers (QCL) can be treated within the closed boundary model for quick estimation of resonant energy levels. The open boundary model allows evaluation of current-voltage characteristics. Using the one, two, and three-dimensional non-equilibrium Green’s functions solver, nano-MOSFETs in the ballistic operation regime can be investigated. Applications 1. Systematically engineer channel transport properties, and boost device performance. 2. Accurate simulation of emerging CMOS technologies, path finding beyond CMOS. 3. Simulate hetero-structure semiconductor devices including quantum effects. 4. Evaluate new materials. When channel length or cross-section dimensions approach the free electron wavelength charge carriers become geometrically confined. This strongly affects device physics, such as electrostatic properties and carrier transport; for accurate modeling, it is vital to account for this behavior. GTS VSP can simulate such devices and thus be used to optimize the structure to obtain a desired performance. In nanometer-scale devices or devices with semiconductor hetero-interfaces, quantum wells, quantum wires, and quantum dots can be formed. Corresponding quantum confinement and transport effects arise (e.g. subbands, resonances, jumps), which can only be fully understood and quantitatively explored by using a full Schrödinger solver. GTS VSP can simulate such structures and deliver insights into their internal properties. New materials can have different and unexpected properties at the macroscopic scale (e.g. terminal characteristics, optical properties). With its customizable material database and its robust solvers VSP is able to predict such material properties in a variety of applications. Solvers Closed-Boundary (CB) Schrödinger Solver - Arbitrary 1D/2D/3D geometries by using unstructured meshes - Substrate and channel orientation - Multi-valley single-band effective mass (EM) Hamiltonian - k·p Hamiltonian with arbitrary number of bands - Lattice stress/strain effect on band structure automatically included - Calculate subband ladder (eigen-energies) and wave-functions Open-Boundary (OB) Schrödinger Solver - Based on non-equilibrium Green’s functions formalism - Multi-valley single-band effective mass (EM) Hamiltonian - Ballistic transport - Current voltage characteristic with resonant tunneling states Mobility calculation on cross-sections - Physical modeling for conductivity and mobility - Based on linearized Boltzmann transport equation (BTE) – beyond Kubo-Greenwood formula - Includes crystal orientation and strain effects - Anisotropic band-structure - Surface roughness scattering (SRS) - Acoustic, optical, and inter-valley phonon scattering (ADP, ODP, IVS) - Polar-optical and remote phonon scattering (POP) - Local and remote Coulomb scattering including dopants, traps, charges both in bulk and on interfaces - Alloy disorder scattering (ADS) Features Models - User-defined N×N unipolar/bipolar k·p band structure models up to second-order in k - Structured or unstructured 3D meshes for real-space and k-space - Smart and efficient solution of Boltzmann transport equation (BTE) in r-, k- and energy-space - Novel gate stacks with remote charges and traps - Support for wide range of channel materials: Si, strained Si, Ge, SiGe, GaAs, InGaAs, and others - Extensive and extensible material database Environment - Integration in the GTS Framework - Intuitive and versatile graphical user interface - Fastest solvers for linear, nonlinear and eigenvalue problems in the industry - Comprehensive scripting interface - Efficient multi-core simulation support Software Development Kit (SDK) - Create one’s own VSP models - Multi-dimensional implementation Future-Proof Device Designs with Real Physics With ever-smaller device features, considering quantum effects is vital for avoiding design risk and understanding device physics. In contrast to empirical descriptions used in most available tools, GTS VSP provides a physical description and insight relying on well-known material properties. GTS VSP is the first commercially available tool capable of accurate simulation of real-world 2D/3D device geometries on a triangular / tetrahedral mesh using a k⋅p Schrödinger Poisson Hamiltonian, including strain effects. GTS VSP enables you to explore, understand and specifically address quantum-effects in recent and future devices, significantly improving efficiency in the design process.
GTS Framework is our base work environment for TCAD applications. Designed as a framework, it embeds various programs (“tools”) in a common workspace, and provides workflow and automation functions like splits/DOE-setups and automatic optimization, backed by structured file storage. All these features are provided in an intuitive (graphical) user interface that is consistent for all tools. Thus, GTS Framework offers unprecedented ease-of-use, allowing even first-time users to get productive within a few hours – proving GTS Framework an extremely efficient working environment. In demanding R&D tasks as well as in production work with tight timelines, being able to focus on the actual simulations and on examining the results is key to efficiency and fast progress. GTS Framework contains all necessary elements, being a solid base for your workflow. It includes essentials such as file I/O, structured data storage, and network integration – up to higher-level functionalities such as setup of experiments and workflows (including splits/DOE and optimization) and automated task distribution in computational clusters. GTS Framework is known for its industry-leading user interface, which helps the beginner yet satisfies the expert – allowing users to choose their preferred way of working. This holds for the 3-level simulator configuration (see below), but e.g. also for its transparent file storage. With the included Tutorials and Application Examples, users get productive even more rapidly. GTS Framework includes an Optimizer as well as features for running experiments with splits or more complex DOE (design of experiment) setups. The respective tasks run locally or on a cluster, automatically distributed via GTS JobServer. Features: - Creation, importing and editing of 1D/2D/3D device geometries - Classical device and circuit simulation, mixed mode - Quantum-mechanical device simulation - Instant 1D/2D/3D visualization of results - Easy-to-use, consistent graphical user interface for all tools (SmartConfig) - Tutorials and examples for quickly achieving results - Scripting tool for complex workflows and data processing (GTS Script, Python) - Powerful and extensible Input Deck Programming language (IPD) - Structured but straight-forward file management for efficent workflow (projects, ToolFolders, NextTool widget) - Remote queuing and execution of simulation jobs / distributed computing (GTS Net+Script+JobServer) - Remote project storage / sharing data in workgroups (GTS Net+JobServer) - Support for multiple platforms (Linux, Windows) - Support for clusters (SGE, LSF, plain TCP/IP) GTS Framework is the preferred environment for using GTS TCAD tools, and it can integrate third-party tools as well. As a comprehensive and flexible platform, GTS Framework helps concentrating on your simulations and results: Implementing workflows is easy and efficient, due to a consistent hierarchical user interface, transparent file management, and distributed computation. The built-in Optimizer and DOE functions provide easy automation of complex experiments. Integration and interoperability with third-party tools make GTS Framework a valuable platform to rely and build upon, both from an operational as well as from a strategic view.
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Profound Physical Device Simulation GTS Nano-Device Simulator (NDS) is the first fully integrated solution for effective physical simulation of nano-scale MOSFETs independent of their technology nodes. NDS is built around a solver for the subband Boltzmann transport equation and provides complete coverage of short-channel effects, including velocity overshoot and source-drain tunneling. NDS is the tool of choice for profound predictive simulation of current and future CMOS technologies. NDS is an advanced device simulation tool based on the solution of the subband Boltzmann transport equation (SBTE) in a critical region of the device such as the channel. NDS incoroprates the electrostatic and near-equilibrium transport from Minimos-NT, and the subband structure calculation and scattering models from VSP. It further extends the SBTE with tunneling transport based on the WKB approximation. As such, NDS can accurately account for material characteristics, crystal orientation, stress, quantum effects, ballistic and kinetic (non-equilibrium) transport effects, all in one package based on solid physical background. The integration with the classical simulator Minimos-NT provides flexibility, stable convergence, and ease-of-use. Despite its sophisticated physical models NDS can be operated just like a classical drift-diffusion-based simulator. In an NDS simulation, a critical region of the device such as the channel is partitioned along the transport direction into slices. After computing an initial solution using Poisson/drift-diffusion, NDS invokes a Schrödinger solver on each slice to account for quantum confinement and to calculate scattering rates. Based on these results, the SBTE is solved in the critical region and SBTE solution converted into an effective mobility that is passed back to the Poisson/drift-diffusion equations. This process is repeated until convergence is reached. NDS can efficiently simulate the whole range of device characteristics using just one simulation setup and run. In this way, the user can obtain both accurate and fast device simulation results for various device architectures, materials and bias points. NDS accounts for all physical phenomena relevant for operation, performance, and reliability of nano devices, such as material characteristics, crystal orientation, stress, ballistic effects, scattering, direct tunneling, band-to-band tunneling, etc. In one single simulator setup, NDS can predict transistor performance parameters like electron mobility, I ON, I OFF, sub-threshold slope, DIBL, leakage, and more — all based on physical simulation relying on material properties rather than empirical models. At the same time, NDS simulations have short turn-around times that make it well-suited for day-to-day use in TCAD. NDS Capabilities Drive Current (I ON) - Boltzmann transport equation - Ballistic and dissipative transport - Velocity overshoot - Quantum resistance - Performance enhancement by channel strain Off-state Leakage (I OFF) - Quantum-mechanical transport - Direct SD-Leakage - Band-to-Band Source-Drain leakage NDS Models NDS leverages the microscopic models available in VSP and combines them with a phase-space transport (PST) solver to solve the SBTE. By using the same band structure and scattering models as VSP, NDS makes it possible to cross-calibrate and transfer model parameters between the two tools - see model building in path-finding for silicon. Band Structure Models are consistent with the ones used in VSP. - Effective mass approximation (EMA) or k·p-based Hamiltonians - Quantum confinement giving rise to subband structure - Arbitrary crystal orientations - Responds to mechanical stress through deformation potentials Scattering Models are consistent with the ones used in VSP. - Acoustic phonon scattering - Optical and inter-valley phonon scattering - Polar-optical phonon scattering - Surface roughness scattering - Coulomb scattering from local and remote sources (dopants, oxide charges and dipoles, traps) - Alloy disorder scattering Phase-Space Transport - Solution of coupled mulit-subband BTE in r–k-space, i.e. phase space for electrons and holes - Electron/hole distribution function of position, momentum, and energy gives detailed insights into device operation at any bias - Semi-classical transport: ballistic transport & scattering - Pauli-exclusion, Fermi-Dirac statistics - Crystal orientation and strain effects automatically included through subband structure - Multi-dimensional: planar and non-planar devices - Adaptive r, k, and energy grids for maximum simulation performance Tunneling Transport - Intra-band source-drain tunneling, Schottky-barrier tunneling, band-to-Band tunneling - Transmission coefficients computed using WKB approximation - Based on numerical computation of complex (sub-)band structure - Seamless integration of tunneling rates within PST - Tunneling included in PST with virtually no added run-time or memory cost - Accuracy verified against ballistic NEGF Environment - Integration in the GTS Framework - Graphical user interface - Sophisticated input-deck database - Multi-core simulation support - Material database extendable via C++ like script language - Import of third-party device geometries and meshes NDS – The Sound Choice for New Challenges True physical simulation is the only way of getting profound data for device shrinking, and for designing, optimizing and predictively evaluating new device architectures and new materials. As a unique, well-maintained, modular and expandable physical modeling platform but one which can deliver accurate results in reasonable time, GTS Nano-Device Simulator is the sound choice for years to come.
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GTS Cell Designer is a tool suite for planning and implementing advanced DTCO workflows – combining layout-based structure generation incorporating detailed technology information (accounting for variability) and advanced physical device and circuit simulation in a parametrized and customizable environment. The Smarter Approach to Design-Technology Co-Optimization Deciding on a technology has big implications from device and cell to circuit and system level. With GTS Cell Designer you can benchmark your technology options (FinFET, NWFET, NSFET, CFET, VFET and more) and get the best design for each. Use the device parameters calculated by GTS Nano Device Simulator (NDS) combined with technology information to obtain an accurate 3D TCAD model of your logic cell. With the automated Spice Model Extractor and the field-solver based parasitics extraction (PEX) you will obtain an accurate circuit representation from a fully consistent TCAD flow. Study cell and device variability, calculate parasitics, power-performance-area (PPA), and gain insight on variability and reliability of the circuits. Optimizations can be run for various aspects – see Cell/Circuit Optimization. - Power, Performance, Area (PPA) - Parasitics - Thermal robustness - Reliability, time-to-failure - Variability, process variations Focus on Your Application Explore key technology parameters which you get from your Cell Designer DTCO workflows. No need for hard-to-obtain process data, no need to dig into process details but focus on achieving your application target Built on Experience, Matured with Industry Feedback Based on its scientific and practical expertise in device simulation, as well as feedback from customers, GTS has prepared example workflows matching the needs of the semiconductor industry. In contrast to conventional, process-related solutions, the required amount of input data for a full-fledged DTCO workflow is moderate and well obtainable – a key aspect when working with contractors. GTS Cell Designer satisfies the demands for reasonable turn-around execution time, and features automatic extraction of key technology parameters as results. With all tools originating from one source, sharing interfaces and data structures, GTS is delivering a consistent solution which is easy-to-use yet powerful and customizable. For Verification – Full TCAD DTCO With the GTS Spice Model Extractor and the GTS Parasitics Extraction as part of the Cell Designer DTCO flow, a completely consistent TCAD-based characterization of the standard cell becomes possible for the first time. Some might say you should never go full TCAD, but with that in mind, the results can be easily verified by running our full TCAD DTCO flow with only four tools in the chain. As shown here, the calculated transients from the TCAD and Spice approach are in excellent agreement giving credit to our fast but accurate Spice DTCO flow. As Cell Designer user you can always verify your results. Modular, yet Compact – a Comprehensive Solution GTS Cell Designer is more than just a combination of individual tools. While each step of the workflow is executed in a separate simulation tool (e.g. Structure, Minimos-NT, VSP) or data processing tool, the workflow (scheduling, distributed execution, post-processing, visualization) is an automated, integrated process in GTS Framework / Cell Designer. Features - Parameterized layout templates as well as a GDSII layout editor - Fast and reliable 3D structure generation, including doping and meshing, fully configurable - Full 3D transient mixed-mode device simulation - Variability, reliability for aging-aware DTCO - Spice Model Extractor: fully automated and scriptable generation of BSIM model cards - Resistance and capacitance extraction of FEOL, MOL and BEOL in one go - Netlist generation - Spice simulation for PPA extraction using internal Python based solution or 3rd Party solver - Data-analysis and post-processing using flexible Python modules GTS Cell Designer alleviates the major issues faced by conventional DTCO approaches. Cell Designer generates realistic but simulation-ready cell geometries without the need for hard-to-obtain process details. You get improved turn-around times and a solid, physically sound base for model calibration. Cell Designer integrates the flow in one familiar user interface, providing automated Spice model and parasitics extraction while still allowing for full customization by DOE/splits, parameters, scripting, etc. Application examples and tutorials ensure a quick start.
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GTS Structure is an intuitive tool for definition and modification of device structures; its state-of-the art graphical user interface facilitates highly efficient use – a significant advantage over conventional solutions. A Powerful Structure Generator and Editor GTS Structure is first-choice for creating simple test devices as well as sophisticated real-world structures. Using the built-in 2D/3D CAD editor, devices can be either designed from scratch, or created/edited based on a comprehensive set of parametrized templates. Alternatively, a module for Layout-based Structure Generation (LSG) capable of reading GDSII mask files can be used to generate device structure from layout using a matching technology rules file. Furthermore, GTS Structure provides an intuitive meshing engine for creation of structured as well as unstructured meshes in two and three dimensions. It offers various manual and automatic mesh refinement options. Device structures can be imported from other TCAD formats / 3rd-party process simulators as well. Structure quantities such as doping and material properties can be defined by analytical functions in the CAD editor, or can be imported from third-party device and geometry files. Features Layout-based Structure Generation (LSG) Inverter cell created from layout (N7 FinFET technology) - Reading mask files - Customizable sets of technology rules - Geometric variability - Generate structures ready for 3D simulation - Multiple structures from same layout Graphical Structure Editing CAD Device Editor - 3D CAD editor for arbitrary device structures - Graphical geometry editor - Graphical doping editor - Extensive library of customizable device templates - Import from 3rd-party process simulators / file formats Graphical Quantity Editing - Quantity editor using analytical expressions - Quantity interpolation from various input files Advanced Meshing 3D unstructured mesh generation - Robust and easy-to-use meshing engine - Unstructured and structured meshes - Quantity-based multiple mesh refinement Environment - Integration in GTS Framework - Intuitive and versatile graphical user interface - Comprehensive scripting interface Versatility and Speed Structure generation and preprocessing is an important prerequisite for accurate and effective device simulation. In order to be useful, a structure generator should provide for simple definition/import and modification of industry-relevant device structures. Generated mesh should reflect relevant structure characteristic and also be suitable for device simulation. GTS Structure provides all those benefits and more. Avoiding the computationally intensive tasks of process simulation or emulation, which additionally require non-disclosed input from a foundry, it uses the fast LSG method to deliver realistic (and large) device structures with meshes optimized for device simulation. For even more realistic structures, structure generation and LSG and can be enhanced with imported geometries, meshes, and attributes.
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