Tcad Device Simulation

[Kensel Whiteman]

Technology computer-aided design (technology CAD or TCAD) is a branch of electronic design automation (EDA) that models semiconductor fabrication and semiconductor device operation. The modeling of the fabrication is termed process TCAD, while the modeling of the device operation is termed device TCAD. Included are the modelling of process steps (such as diffusion and ion implantation), and modelling of the behavior of the electrical devices based on fundamental physics,[2][3] such as the doping profiles of the devices. TCAD may also include the creation of "compact models" (such as the well known SPICE transistor models), which try to capture the electrical behavior of such devices but do not generally derive them from the underlying physics. SPICE simulator itself is usually considered as part of EDA rather than TCAD.

The goals of TCAD start from the physical description of integrated circuit devices, considering both the physical configuration and related device properties, and build the links between the broad range of physics and electrical behavior models that support circuit design. Physics-based modeling of devices, in distributed and lumped forms, is an essential part of the IC process development. It seeks to quantify the underlying understanding of the technology and abstract that knowledge to the device design level, including extraction of the key parameters[4] that support circuit design and statistical metrology.

IC development for more than a quarter-century has been dominated by the MOS technology. In the 1970s and 1980s NMOS was favored owing to speed and area advantages, coupled with technology limitations and concerns related to isolation, parasitic effects and process complexity. During that era of NMOS-dominated LSI and the emergence of VLSI, the fundamental scaling laws of MOS technology were codified and broadly applied.[7] It was also during this period that TCAD reached maturity in terms of realizing robust process modeling (primarily one-dimensional) which then became an integral technology design tool, used universally across the industry.[8] At the same time device simulation, dominantly two-dimensional owing to the nature of MOS devices, became the work-horse of technologists in the design and scaling of devices.[9] The transition from NMOS to CMOS technology resulted in the necessity of tightly coupled and fully 2D simulators for process and device simulations. This third generation of TCAD tools became critical to address the full complexity of twin-well CMOS technology (see Figure 3a), including issues of design rules and parasitic effects such as latchup.[10][11] An abbreviated but prospective view of this period, through the mid-1980s, is given in;[12] and from the point of view of how TCAD tools were used in the design process.[13]

Figure 1 depicts a hierarchy of process, device and circuit levels of simulation tools. On each side of the boxes indicating modeling level are icons that schematically depict representative applications for TCAD. The left side gives emphasis to Design For Manufacturing (DFM) issues such as: shallow-trench isolation (STI), extra features required for phase-shift masking (PSM) and challenges for multi-level interconnects that include processing issues of chemical-mechanical planarization (CMP), and the need to consider electro-magnetic effects using electromagnetic field solvers. The right side icons show the more traditional hierarchy of expected TCAD results and applications: complete process simulations of the intrinsic devices, predictions of drive current scaling and extraction of technology files for the complete set of devices and parasitics.

Figure 2 again looks at TCAD capabilities but this time more in the context of design flow information and how this relates to the physical layers and modeling of the electronic design automation (EDA) world. Here the simulation levels of process and device modeling are considered as integral capabilities (within TCAD) that together provide the "mapping" from mask-level information to the functional capabilities needed at the EDA level such as compact models ("technology files") and even higher-level behavioral models. Also shown is the extraction and electrical rule checking (ERC); this indicates that many of the details that to date have been embedded in analytical formulations, may in fact also be linked to the deeper TCAD level in order to support the growing complexity of technology scaling.

Current major suppliers of TCAD tools include Delphea, Synopsys, Silvaco, Crosslight Software, Cogenda Software and Global TCAD Solutions. The open source GSS,[15] Archimedes,[16] Aeneas,[17] NanoTCAD ViDES, DEVSIM,[18] GMPT and GENIUS have some of the capabilities of the commercial products.

Technology Computer-Aided Design (TCAD) refers to the use of computer simulations to develop and optimize semiconductor process technologies and devices. Synopsys TCAD offers a comprehensive suite of products that includes industry-leading process and device simulation tools, as well as a powerful graphical user interface (GUI) driven simulation environment for managing simulation tasks and analyzing simulation results. In addition, Synopsys TCAD provides tools for interconnect modeling and extraction, providing critical parasitic information for optimizing chip performance.

Visit Synopsys Booth on Jun 3-6, 2024 at ISPSD in the concert hall Die Glocke, Bremen, Germany. Come and meet with our team to learn about how Synopsys TCAD can be impactful to all your power device applications.

QuantumATK simulates the properties and transport mechanisms of novel materials and device structures, enabling the down-selection of promising materials for further exploration and the TCAD-level simulation of advanced devices before wafer-based data is available. Sentaurus Materials Workbench provides a link between QuantumATK output and TCAD models implemented in Sentaurus simulators.

Sentaurus Process is the industry standard for simulating the fabrication steps of semiconductor processes, ranging from silicon-based logic, memory, power, and CIS technologies to SiC-based technologies. Sentaurus Process supports the modeling of implantation, diffusion and dopant activation, thermal oxidation, mechanical stress, and epitaxial growth. Sentaurus Topography supports the modeling of topographical steps including etching, deposition, CMP, and electroplating.

Sentaurus Process Explorer is a fast 3D process emulator used to identify and correct process integration issues during technology development. Sentaurus Process Explorer produces highly realistic 3D representations of process structures using GDSII mask data and a process recipe as input. Sentaurus Process Explorer is linked to the Synopsys TCAD simulators, such as Raphael FX, to enable the high accuracy RC extraction in Design Technology Co-Optimization (DTCO) applications.

Sentaurus Structure Editor is a device structure editor used to create structures for device simulation when process simulation is not required. Sentaurus Structure Editor uses geometric primitives powered by the ACIS geometry kernel to render complex device shapes. A graphical user interface serves as the front end for mesh generation engines available in Sentaurus Process and Sentaurus Device. The Sentaurus Structure Editor command language recreates the device structure in batch mode as part of a simulation flow.

Sentaurus Device is the industry standard for simulating the electrical characteristics of silicon-based and compound semiconductor devices as a response to external electrical, thermal or optical boundary conditions. Advanced physical models for quantum effects, ballistic transport, tunneling processes, stress engineering, hot carrier effects, and other transport phenomena support the optimization of state-of-the-art devices ranging from advanced logic and memory to analog, power and optoelectronics devices.

Interconnect simulation tools address the electrical and reliability performance of middle-of-line and back-end-of-line interconnect structures. Raphael FX is the industry gold-standard 3D field solver for extracting the resistance and capacitance of detailed interconnect structures, SRAM cells, and standard cells in DTCO. Sentaurus Interconnect simulates the reliability of interconnect structures based on the mechanical stress generated through thermal processing and externally applied forces.

Sentaurus Workbench is a complete graphical environment for creating, managing, executing, and analyzing TCAD simulations. Its intuitive graphical user interface (GUI) allows users to efficiently navigate and automate the typical tasks associated with running TCAD simulations such as managing the information flow, including preprocessing of user input files, parameterizing projects, setting up and executing tool instances, optimization, and visualizing results. Sentaurus Visual is an advanced visualization tool for TCAD data. It includes extensive capabilities for plotting and interactively manipulating xy data as well as 2D and 3D TCAD structures.

Mystic extracts compact model parameters (standard SPICE models, macro models, Verilog-A models) from Sentaurus TCAD output, enabling technology development and DTCO teams to simulate the impact of new transistor designs using circuit-level metrics before wafers are available. The TCAD-to-SPICE flow also supports the simulation of the impact of process variability at the circuit-level through the extraction of variation-aware compact models using the variability engine Garand VE and the model card generator RandomSpice.

Synopsys TCAD tools are used by process and device engineers at all major semiconductor companies to develop and optimize semiconductor technologies. Occasionally, the tools need to be calibrated for a particular technology, so that they can be more predictive for future nodes. Synopsys TCAD Services offers calibration, simulation, model development, and consulting to customers. Our team targets the optimization of processes and devices using TCAD tools and the investigation of technology development and manufacturing issues using a vast knowledge base of proven process and device modeling methods.

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