Silvaco TCAD
Leader in Power Device TechnologyDevelopment

Silvaco TCAD for Silicon andSilicon Carbide Technology
Process Simulation
Device Simulation
ExamplesCopyright │ ©2023 Silvaco, Inc.

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Victory Process for Si and SiC Power Devices
Virtualize your process flow. Optimize the next generation power devices through virtualfabrication
Full 2D/3D TCAD Process Solution• Build, debug, calibrate in fast 2D• Easy transition to realistic 3D for full 3D technology design• Seamless integration into Device Simulation
Process simulation for Si and SiC• Etch & Deposition• Implantation• Dopant Activation• Oxidation• Open Model Library and Material database• Allows for user customizability
Silicon Split Gate Trench UMOSFET
from Victory ProcessCopyright │ ©2023 Silvaco, Inc.

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Etch and Deposition for Next Generation Devices
New power devices utilize multiple etch and deposition steps to produce trenches, spacers, anddielectric layers. Capturing material geometry faithfully ensures TCAD simulation matches thefab.

• GDSII driven TCAD, connecting fab to TCAD
• Import layout to use as masks for any process step
• Simple geometric models for fast simulating etch & deposition
steps

4H-SiC• Define etch/deposition thicknesses and a geometric model• Detailed physical models for deeper understanding of yourprocess steps• Define deposition/etch rates for each material• Sticking factors, flux parameters• Useful for understand visibility effects

Emulation of SiC Microtrench
formation with time evolution
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Implantation Accuracy with Victory Process
Fabrication processes include numerous implantations steps. Capturing physics-accurate
implantation profiles allows optimization of process conditions for the best performing, high yielddevices

Physical Implantation via Monte Carlo
Implantation• User-Definable Implant Properties• Substrate type/orientation, wafer miscut, angle, dose andenergy• Well calibrated stopping within crystal channels and random
direction• Crystal Damage & Scattering due to damage accumulation

Empirical Methods to define doping in process• Doping profiles by analytical distribution function• Quickly add Gaussian doping• Doping profiles defined by external data files• Use SIMS profiles to build your TCAD process

Copyright │ ©2023 Silvaco, Inc.

Implant distribution at the Silicon surface shows
pronounced lateral channeling5Electrical Activation During Fabrication

Dopant Activation Models calibrated for both Si & SiC• Two major activation models: Empirical and Transient• Empirical: Instantaneous relationship between active andnon-active concentrations• Transient: Adds transient partial differential equation to theempirical model• Table Method for inserting user input data
• Allows users to incorporate proprietary or new experimental
activation data with ease

Ratio Active/Total

Incomplete activation of dopants can dictate device performance, especially in Silicon Carbide.
Modeling electrical activation as part of process simulation captures dopant concentrations
accurately

Total Conc
Activation Ratio vs Concentrationfor 4H-SiC at 1700C

Copyright │ ©2023 Silvaco, Inc.

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Robust Oxidation Simulation
Simulation of 3D oxidation is a challenging numerical problem. Victory Process is capable ofefficiently and accuracy modeling key oxidation steps for Silicon and Silicon Carbide devices.

Oxidation Simulations available for Si & SiC
SiO2

AnisotropicOxidation Effects for
4H-SiC
Copyright │ ©2023 Silvaco, Inc.

Silicon

SiO24H-SiC
PolySi• Well calibrated for Silicon & Silicon Carbide• Fully 3D Anisotropic Oxidation Model for 4H-SiC• Each crystal plane will have separate oxidation rates• Well calibrated to experimental results• Useful for understanding oxidation in trench devices

LOCOS Oxidation forSilicon Power Device
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Victory Device for Si and SiC Power Devices
Victory Device meets the breadth and depth of power device simulation needs
Simulate DC, AC and transient electrical simulation• Understand how your device performs in any scenario
Self-Heating Simulation• Gain insight into self-heating effects that influences electrical physics

Reliability and Radiation• Simulate device degradation due to electrical stress, as well as radiation
effects (TID, DD, SEB)
MixedMode circuit/device simulation• Simulate TCAD devices within a SPICE circuit
User-customizable physical models & material parameters• Calibrate any simulated device to your experimental data
• Novel wide bandgap materials can be simulated by adjusting the physicalparameters
Advance numerical solvers and methods• Multithreaded simulations and numerical extended precision available for themore difficult simulations

Copyright │ ©2023 Silvaco, Inc.

Anisotropic Mobility ofSiC HexFET
8Mobility Models for Accurate Simulation
Using the correct mobility models are essential for simulating your device properly
Mobility Models in Si•••

30 years of TCAD experience in SiliconMultiple models for low/high field mobility for SiliconMultiple inversion layer models

Mobility Models in SiC•Calibrated parameters for SiC for many low/high field mobilitymodels•SiC Inversion Layer Mobility Model– Accurately model the low mobility in the channel– 4 major mobility components that can be adjusted to fit• Bulk Mobility, Surface Roughness, Acoustic Phonon Scattering, Coulomb
Scattering•Anisotropic Mobility– Users can specify mobilities for different orientations inside the device
Copyright │ ©2023 Silvaco, Inc.

Inversion Layer Mobility vsElectric field. Considering
combined effects of mobility
degradation effects
9Essential Physical Models for Power Devices
Victory Device can simulate all the important effects needed to understand your power device
whether it’s silicon or a wideband gap material
Impact Ionization
Understand how breakdown can occur in your device

Si– Anisotropic Impact Ionization for SiC– Multiple impact ionization models for•

BV

User-definable orientation of crystal axis

Silicon– Two-Level Model for SiC for hex and cubic sites

SiO2Can directly or indirect effect mobility and other physical properties in device

PolySi

Incomplete Ionization of Impurities

Bulk and Interface State Models– Correctly model the interface traps and charges between a SiC/Oxide interface

Contact modeling for Si & SiC– Definable work-function and contact properties (resistance, workfunction, tunneling)– Schottky Parabolic Field Emission Model for 4H-SiC– Ability to add lumped resistance/inductance or distributed resistance

Copyright │ ©2023 Silvaco, Inc.

Breakdown of Silicon Power Deviceand Impact Generation Rate
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Silicon and Silicon CarbideExamples

Copyright │ ©2023 Silvaco, Inc.

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3D Design – Layout and Process Optimization
Trench Shape Effects
Breakdown voltage• Process->Mesh->Device

Sharp Edge

RoundedAngledTrench

Compare 3 different structures
1. Manhattan - Right angle
corner, vertical trench
2. Rounded corner, verticaltrench sidewall
3. Rounder corner sloped trenchsidewall
Device 1
Copyright │ ©2023 Silvaco, Inc.

Device 2

Device 312

3D Trench Shape Effect on Breakdown Voltage
Trench Shape Effects• Anisotropic Impact Ionization• BV can be increased by 30% using
rounded layout and angled trench• Impact ionization not occurring onlyat the corner of the trench#1 #2 #3

2D Simulation(reference)

Device 1

Device 2

Copyright │ ©2023 Silvaco, Inc.

Device 313

Split-Gate Trench UMOSFET
Delaunay mesh to resolve complex 3D geometry
features (a) and doping profiles (b)Victory Process simulation of key process steps
to fabricate the Split-Gate UMOSFET
Copyright │ ©2023 Silvaco, Inc.

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Split-Gate Trench UMOSFET

Victory Device can handle complex 3D geometries, for efficient and accurate device characterization
Capacitances vs Drain
Voltage

IdVg

IdVd

Breakdown

Copyright │ ©2023 Silvaco, Inc.

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Silicon Carbide DMOS Process and Device
Full Process Simulation to Device Simulation
Based on IEEE EDL paper:“600 V 4H-SiC MOSFETs Fabricated in Commercial Foundry
With Reduced Gate Oxide Thickness of 27 nm to Achieve
IGBT-Compatible Gate Drive of 15V”

Copyright │ ©2023 Silvaco, Inc.

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SiC Trench MOSFET Process & Device
Full Process Simulation to Device
Simulation
OFFSET statement used inVictory Mesh
• Generates offset slices at aninterface• Can be used with Delaunay
Remeshing– Mesh conforms to curvedinterface• Useful for inversion layers ofnon–planar devices

IdVg Characteristics
Copyright │ ©2023 Silvaco, Inc.

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SiC Super-Junction Device••••

Full Process Simulation to Device Simulation
Monte Carlo Implantation
Charge Balance of active dopants
Simulates IV and BV

BV Curve

ID-VG
Net Doping
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Impact Generation18

Silvaco is leading theway for next
generation Power
Device Technology
simulation

BCD
Power Diode
Thyristor
IGBT

Copyright │ ©2023 Silvaco, Inc.

SiC

DMOS
TrenchMOS
JBSGaN

Lateral HEMT
Vertical HEMTP-GaN Gate HEMTSilicon19