S-Pisces - 2D Silicon Device Simulator
Simulate silicon based technologies
Use drift-diffusion and energy balance transport equations

Device Simulation Framework

Atlas is a 2D and 3D device simulator that performs DC, AC, and transient analysis for silicon, binary, ternary, and quaternary material-based devices. Atlas enables the characterization and optimization of semiconductor devices for a wide range of technologies.


Device simulation helps users understand and depict the physical processes in a device and to make reliable predictions of the behavior of the next device generation. Two-dimensional device simulations with properly selected calibrated models and a very well-defined appropriate mesh structure are very useful for predictive parametric analysis of novel device structures. Two- and three-dimensional modeling and simulation processes help users obtain a better understanding of the properties and behavior of new and current devices. This helps provide improved reliability and scalability, while also helping to increase development speed and reduce risks and uncertainties.


  • Accurately characterizes physics-based devices in 2D or 3D for electrical, optical, and thermal performance without costly split-lot experiments
  • Solves yield and process variation problems for optimal combination of speed, power, density, breakdown, leakage, luminosity, and reliability
  • Fully integrated with Athena process simulation software, comprehensive visualization package, extensive database of examples, and simple device entry
  • Largest selection of silicon, III-V, II-VI, IV-IV, or polymer/organic technologies, including CMOS, bipolar, high voltage power device, VCSEL, TFT, optoelectronic, LASER, LED, CCD, sensor, fuse, NVM, ferro-electric, SOI, Fin-FET, HEMT, and HBT
  • Connects TCAD to tapeout with direct import of Atlas results into Utmost for SPICE parameter extraction
  • Parallel processing supported on multi-core, multiple processor SMP machines and distributed computing
  • Worldwide support
  • Silvaco’s secure encryption for maximum customer and third party intellectual property protection


  • Electrical, thermal and optical characterization of advanced semiconductor devices allows for device performance optimization
  • Addresses challenges of current technologies to help users reduce product development time
  • Exploration of novel device technologies for next-generation devices



Atlas’s capabilities optimizes electrical and thermal behavior of power devices, such as power MOS, LDMOS, SOI, thyristors and IGBTs. The extended precision numerics used by Atlas allow the stable and accurate simulation of wide bandgap materials such SiC and GaN. These devices can also be embedded with a circuit and simulated by the built-in SPICE circuit simulator.

Location of the hot spot and current flow with the device in a latched state


Advanced CMOS

Hot carrier, stress and quantum correction and tunneling models allow for the simulation of advanced CMOS devices such as FinFET and FDSOI.

Wave functions in the 10 nm diameter channel of surround
gate transistor for the valley with in-plane effective masses mx=my=mt=0.19m0 and
out of plane mass mz=me=0.91m0


Self-consistent quantum electron density in a 14X14
nm rectangular structure doped to 1020 cm-3 as found by fast product-space
2D Schrodinger solver on a mesh with 5041 grid points.

Compound Semiconductor

Support for a wide range of compound materials, such as SiGe, GaAs, AlGaAs, InP, SiC, GaN, AlGaN and InGaN, allow the characterization of complex compound semiconductor devices.

Solution files produced by Blaze contain internal device variables such as electron concentration. The Schottky barrier creates a depletion layer below the gate. Electrons accumulate in the narrow band-gap materials in the channel.

Potential variation of the conduction band edge, as well as the first seven bound state energy levels under the gate of a GaAs/ AlGaAs HEMT device. Here we can see that there is confinement due to the heterojunction as well as a potential well due to depletion in the AlGaAs top layer.



Atlas’ support for advanced defect models allows the characterization of thin-film devices.

A top gate n-channel Poly-Si TFT. This type of device is used for driving active matrix display elements. Contours of the potential at 0V are displayed. The Grain size is 600nm, Poly-Si thickness is 50nm and Gate oxide thickness is 140nm.


The metal electrode geometry is important for devices such a bottom gate a-Si TFTs. TFT 3D correctly accounts for these geometrical effects on the current and capacitance.

A bottom gate a-Si TFT device at Vd=1V



The optoelectronic response of devices such as solar cells, CMOS image sensors, LEDs oLEDs, LASERs and VCSELS can be simulated using Atlas. Mode solver, ray-trace, Transfer Matrix Method (TMM), Finite Difference Time Domain (FDTD) optical method are available.


A device structure plot of a micro-lens CCD created with Athena. The geometric ray trace data generated by Luminous is overlaid on the structure. Geometric ray tracing capabilities enable the analysis of complex non-planar structures for optimizing collection efficiency and reducing cross-talk. The photogeneration rate is calculated based on the local optical intensity provided by the ray tracing.

3 dimensional raytrace for a particular color into a cell of an imaging array

Application of finite difference time domain method to analyze the LED output coupling for photonic coupling devices, such as photonic crystals and gratings



Radiation effects such as Single Event Effects (Single Event Upset, Single Event Burnout, Singlet Event Gate Rupture), total dose and dose rate can be simulated in steady-state, AC and transient.

Definition of the SEU strikes incorporates generation of e-h pairs as a function of time, distance from the particle track center as well as distance from the particle entry point. Entry and exit points are arbitrary and multiple particles strikes are supported.


Novel Devices

Models for ferroelectric dielectric, magnetic, and ion transport allow novel devices to be characterized.

Simulated unsaturated ferroelectric polarization curves for different drain bias values

Atlas Modules


2D Silicon Device Simulator. S-Pisces is an advanced 2D device simulator for silicon based technologies that incorporates both drift-diffusion and energy balance transport equations. A large selection of physical models are available which include surface/bulk mobility, recombination, impact ionization and tunneling models.



2D Optoelectric Device Simulator. Luminous is an advanced device simulator specially designed to model light absorption and photogeneration in non-planar semiconductor devices. Exact solutions for general optical sources are obtained using geometric ray tracing.


Organic Solar

Organic Solar Cell and Photodetector Simulator. Organic Solar module enables Atlas to simulate the electrical and optical properties of organic solar cell devices, photodetectors and image sensors. Organic Solar allows steady-state, transient, and AC simulation of the electrical and optical behavior of photovoltaic organic devices. The exciton densities, diffusion, generation/recombination and dissociation characteristics can all be simulated.



Circuit Simulation for Advanced 2D Devices. MixedMode is a circuit simulator that includes physically-based devices in addition to compact analytical models. Physically-based devices are used when accurate compact models do not exist, or when devices that play a critical role must be simulated with very high accuracy. Physically-based devices are placed in a SPICE netlist circuit description and may be simulated using any combination of Atlas 2D modules. The MixedMode XL license enables MixedMode users to use an unlimited number of physical devices or compact model elements in their circuits.



Vertical Cavity Surface Emitting Laser Simulations. VCSEL is used in conjunction with the Atlas framework to produce physically based simulations of vertical cavity surface emitting lasers (VCSELs). VCSEL joins sophisticated device simulation to obtain electrical and thermal behavior with state of the art models for optical behavior.



2D Simulation Models for Quantum Mechanical Effects. Quantum provides a set of models for simulation of various effects of quantum confinement and quantum transport of carriers in semiconductor devices. A Schrodinger – Poisson solver allows calculation of bound state energies and associated carrier wave functions self consistently with electrostatic potential. Schrodinger solver can be combined with the Non-equilibrium Green’s Function (NEGF) approach in order to model ballistic quantum transport in 2D or cylindrical devices with strong transverse confinement. Quantum also includes models for the quantum mechanical corrections to drift-diffusion and hydrodynamic equations.



The Magnetic module enables the Atlas device simulator to incorporate the effects of an externally applied magnetic field on the device behavior. The dynamics of the charge carrier motion are modified by the addition of the Lorentz force.



Radiation Effects Module. The REM Radiation Effect Module allows Atlas 2D/3D and Victory 3D simulators to model total dose, dose rate and SEU effects in semiconductors through the generation of defect states, fixed charge, and charge transport within insulating materials.



2D Device Simulator for Advanced Materials. Blaze simulates devices fabricated using advanced materials. Includes a library of physical models and material parameters for binary, ternary and quaternary semiconductors.



2D Non-Isothermal Device Simulator. Giga combined with S-Pisces and Blaze device simulators allows simulation of self heating effects. Models in Giga include heat generation, heat flow, lattice heating, heat sinks, and effects of local temperature on physical constants.




2D Light Emitting Diode Simulator. LED is a module used for simulation and analysis of light emitting diodes. It is integrated with the Blaze simulator and allows simulation of electrical, optical and thermal behavior of light emitting diodes.



2D Amorphous and Polycrystaline Device Simulator. TFT is an advanced device technology simulator equipped with the physical models and specialized numerical techniques required to simulate amorphous or polysilicon devices including thin film transistors. Specialized applications include large area display electronics such as Flat Panel Displays (FPDs) and solar cells.


Organic Display

OLED And OTFT Organic Display Simulator. Organic Display module enables Atlas to simulate the electrical and optical properties of organic display devices such as OTFTs and OLEDs. Organic Display allows steady-state and transient simulation of the electrical and optical behavior of active organic devices including singlet and triplet exciton densities, dopant exciton density, and optical emission characteristics.



Semiconductor Laser Diode Simulator. Laser is the world’s first commercially available simulator for semiconductor laser diodes. Laser works in conjunction with Blaze in the Atlas framework to provide numerical solutions for the electrical behavior (DC and transient responses) and optical behavior of edge emitting Fabry-Perot type lasers diodes.



Ferroelectric Field Dependent Permitivity Model. Ferro has been developed to combine the charge-sheet model of FET with Maxwell’s first equation which describes the properties of ferroelectric film. The model can accurately predict the static I-V behavior of these devices as well as the dynamic response in transient and small signal modes.



2D Small Signal Noise Simulator. Noise combined with S-Pisces or Blaze allows analysis of the small-signal noise generated within semiconductor devices. Noise provides accurate characterization of all small-signal noise sources and extracts figures of merit which are essential for optimizating circuit design.