3D Device Simulator

Device 3D is a physics based 3D device simulator for any device type and includes material properties for the commonly used semiconductor materials in use today. The physical phenomenon that can be simulated self consistently with the semiconductor equations include photon absorption, photon emission, bulk and interface traps, magnetic fields, self heating, ionizing radiation strikes, hot carrier and tunneling effects. This allows simulation of devices such as solar cells, CMOS sensors, LEDs, TFTs, EPROMs, aggressive technology CMOS and power devices. Device 3D uses a simple, intuitive and flexible syntax and runtime environment together with excellent 2D and 3D visualization tools compliment this powerful product.

Nano Scale Devices

Fin FETs, nano wire FETs and standard FETs at aggressive technology nodes all can be simulated using Device 3D.

Fin FET

Fin FET example created directly using Device 3D syntax, showing doping electron distribution and IV characteristics using both drift-diffusion and Bohm Quantum Potential 3D models.

Phosphorus concentration for a FinFET device. Electron concentration showing depletion region under the gate.

 

Id/Vg characteristics comparing drift-diffusion and Bohm Quantum Potential (BQP) solutions.

 

Nano Wire FET

A recent addition to the Quantum modeling capability has enabled simulation of the strong quantum confinement effect in quantum wire devices. To model the effects of quantum confinement, Quantum 3D allows a self-consistent solution of the 1D or arbitrary shape 2D Schrodinger and 3D Poisson equations.


Contours of electron wavefunctions on the surface of 3D structures, found by 1D (left) and 2D (right) Schrodinger equation solved self-consistently with 3D Poisson equation.

 


Device schematic (top left), isosurface of total current density (bottom) and isosurface of electron density (top right) of a 3D silicon nanowire FET with flared-up source and drain regions, computed with coupled mode space NEGF approach.

 


Schematics (left) and I-V characteristics (right) of a Si nanowire transistor with uniform channel cross-section, computed with uncoupled mode space NEGF approach.

 

Aggressive Geometry 50nm MOSFET

In this example, the 50nm MOSFET structure was created using Victory Process. Victory Process is a process simulator that allows creation of Device 3D compatible structures following arbitrary shape mask layout driven 3D process simulation.

The mask set, process simulated shape, converted Device 3D structure and electrical characteristics are shown below.

 

Mask layout Process simulated structure

 


Converted Atlas structure with and without gate spacer.

 

Cross section of net doping.
IV characteristics for different channel doping.

 

Quantum Well Analysis

Analysis of bound states and wave functions are possible in 3D quantum devices. Here, analysis for a single quantum well and a triple quantum well design are shown as examples.

SQW Analysis

3QW Analysis

GaN/InGaN/GaN single Quantum Well (QW) and delta sandwiched QW quantization.

 

Memory Devices

Hot carrier injection and tunnelling models allow the injection of charge on to floating gates, necessary for the simulation of memory devices. An EPROM example is shown below.

EPROM electron concentration EPROM potential distribution shown as an isosurface plot

 

IV characteristics before and after programing Floating gate integrated charge as a function of time

 

Opto-Electronics

Ray tracing, optical absorption and optically generated carriers are solved self consistently with all other semiconductor equations allowing simulation of light absorbing devices such as photo-diodes and CMOS sensors. Photon generation equations also allow simulation of optically emitting devices such as light emitting diodes (LEDs).

Photodiode Simulation

InP/InGaAsP/InGaAs/InP photo diode Dark and illuminated anode current versus anode voltage at 1.55µm

 

CMOS Simulation

Advanced 3D ray tracing capability of Luminous 3D can be used to evaluate spatial resolution and crosstalk issues in imaging arrays CMOS sensor potential distribution

 

GaN LED Simulation


Radiative Recombination Rate distributions

 

Thin Film Transistors

The electrical characteristics of thin film transistors (TFTs) are dominated by the existence of bulk and surface traps. In Device 3D these defects can be described as a continuum of defects throughout the bandgap, or can be specified individually. The insulating substrates that these devices are fabricate on (usually glass), are often poor conductors of heat. The additional modelling of self heating effects can often have a considerable effect on device electrical characteristics.

Octagonal array of TFT elements. The contacts and the SiO2 layers have been made transparent so that the amorphous Si element can be seen more clearly.

 

Transfer characteristics for a poly-Si TFT.
Id/Vd characteristics with and without lattice temperature modeling.

 

Power Devices

Understanding the operation of power devices is an excellent application for 3D TCAD device modelling. Power devices, such as thyristors and triacs etc, often have electrical characteristics dominated by semiconductor phenomenon that occurs deep in the bulk silicon of the device which is difficult to probe directly with measurements. 3D TCAD simulation allows analysis of exactly what is going on throughout the whole device and any time instant during switching transients etc. Below is an example of a UMOS HexFET simulation.

Potential distribution for a UMOS HexFET.
Id/Vg characteristics for a UMOS HexFET.

 

Adding External Circuit Elements

Power devices are often tested and characterized with other connected passive load elements. Here a bipolar transistor is tested with lumped elements attached to its terminals.

Mixed device and circuit element simulation

 

Maximum device temperature and base current as a function of time

 

Self Heating

A number of power devices heat up considerably during normal operation. Simulation of self heating effects can detect possible hot spots in your design. Here a simple resistor is used to demonstrate heating effects. Self heating effects can be modeled for any arbitrary device.

Temperature plot at the surface of the passivation oxide due to thermal heating of a buried interconnect aluminum line

 

External Heat Flow

Once the thermal output of the power devices has been analyzed at a device level, individual or numerous power devices sharing a common heat sink or package can be analyzed as simple heat sources using the Thermal 3D simulator in order to gauge how hot the package will get after final installation.

GaN HEMT device fabricated onto a Silicon Carbide substrate mounted onto a copper heat sink

 


Atlas 3D Modules

Giga 3D

3D Non-Isothermal Device Simulator. Giga 3D module extends Device 3D by incorporating the effects of self-heating into a device simulation. It includes models for heat sources, heat sinks, heat capacity and thermal conduction. Physical and model parameters become dependent on the local lattice temperature where appropriate, allowing self-consistent coupling between the semiconductor device equations and the lattice temperature.

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TFT 3D

3D Amorphous and Polycrystaline Device Simulator. TFT 3D is an advanced device technology simulator equipped with the physical models and specialized numerical techniques required to simulate amorphous or polysilicon devices in 3D. TFT3D models the electrical effects of the distribution of defect states in the band gap of non-crystalline materials. Users can specify the Density Of States (DOS) as a function of energy for amorphous silicon and polysilicon for grain and grain boundaries as well as the capture cross-sections/lifetimes for electrons and holes.

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Magnetic 3D

3D Magnetic Device Simulator. Magnetic 3D module enables the Atlas device simulator to incorporate the effects of an externally applied magnetic field on the device behaviour. The dynamics of the charge carrier motion is modified by the addition of the Lorentz force. This force is proportional to the vector product of the carrier velocity and the applied magnetic flux density vector. The Magnetic 3D module allows the consequent changes to current flow and potential distributions to be calculated.

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LED 3D

3D Light Emitting Diode Simulator. LED 3D is a module used for simulation and analysis of light emitting diodes. LED 3D is integrated in the Atlas framework and allows simulation of electrical, optical and thermal behavior of light emitting diodes in 3D.

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Thermal 3D

Thermal packaging simulator. Thermal 3D is a general heatflow simulation module that predicts heatflow from any power generating devices (not limited to semiconductor devices), typically through a substrate and into the package and/or heatsink via the bonding medium. Operating temperatures for packaged and heat sinked devices or systems can be predicted for the design and optimization phase or for general system analysis.

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Luminous 3D

3D Optoelectric Device Simulator. Luminous 3D is an advanced simulator specially designed for analysis of optical response of non-planar semiconductor devices in three dimensions.

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MixedMode 3D

Circuit Simulation for Advanced 3D Devices. MixedMode 3D is a circuit simulator that includes physically-based 3D 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 Atlas3D modules. The MixedModeXL license enables MixedMode3D users to use an unlimited number of physical devices or compact model elements in their circuits. This allows more sophisticated circuit definition.

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Quantum 3D

3D Simulation Models for Quantum Mechanical Effects. Quantum 3D 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 Non-equilibrium Green’s Function (NEGF) approach in order to model ballistic quantum transport in 3D devices with strong transverse confinement.

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