Electrical and Thermal Simulators for Silicon Carbide

Power Electronics

Akin Akturk, Zeynep Dilli, Neil Goldsman,Siddharth Potbhare, James McGarrity, Brendan Cusack,

Miles Miller-Dickson, Lalitto Sarker, Chris Segni

Our Place in the SiC World

CoolCAD Electronics

–CoolSPICE-

SiC

Cadence-Spectre

-Verilog-A

Synopsys-Saber

Mathworks-Simulink

-Simpower

Ansoft-

Simplorer

Mentor Graphics

-Flotherm

SiC Models Y N N N N N

Simulation Environment Y Y Y Y Y N

Thermal Modeling Y N N N Y Y

Circuit Design Y Y Y Y Y NCo-Design Electricaland Thermal Y N N N N N

And this is why we are building CoolSPICE-SiC ..

In 2020, SiC will be everywhere….

And these companies will play a role in that…Sectors Companies

Devices/Components USCi, Cree, ROHM, Infineon, Powerex, etc.

Design Tools CoolCADSystems ARL, ONR, Delta, GE, etc.

Service & Distribution Pepco, ABB, etc.

Silicon Carbide Device, Module, System Simulations

CoolSPICE Electrical and Thermal Circuit

Simulator

SiC Power Module and System Design

Student version is available online

> ~8000 downloads

http://coolcadelectronics.com/coolspice/

0 5 10 15 20 250

5

10

15

Dra

in C

urre

nt (A

)

0 5 10 15 20 250

100

200

300

Time (us)

Dra

in V

olta

ge (V

)

Power MOSFET Parameter Set

Output Signalsfrom Circuit

Input Signalsto Circuit

Extraction by Matching Simulation Results to

Measured Data

Device Parameters:Standard BSIM, plus

CoolCAD enhancements for power MOSFETs

Agreement with Temperature-Dependent DC Operation

Solid lines: CoolSPICE simulationsSymbols: Measurements

Agreement with CV Measurements forC2M0160120D 18A-19A 160 mΩ

First model CGD using QGD

CalculatedExtracted

CGD = dQ / dVCalculatedExtracted

SiC Device Libraries

Manufacturer Model_No Device_Type

Have in-

house?Current Rating (A)

Voltage Rating (V)

Power Rating (W)

Cissoid Neptune CHT-PLA8543C MOSFET y 10 1200 30Cree C2M0025120D MOSFET y 90 1200 463Cree C2M0040120D MOSFET y 60 1200 330Cree C2M0080120D MOSFET y 36 1200 208Cree C2M0160120D MOSFET y 19 1200 125Cree C2M0280120 MOSFET y 10 1200 62.5Cree C2M1000170D MOSFET y 4.9 1700 69Cree CMF10120D MOSFET y 24 1200 152Cree CMF20120D MOSFET y 42 1200 150GE Internal Part MOSFET yMicrosemi APT40SM120B MOSFET n 40 1200 273ROHM SCH2080KEC MOSFET y 40 1200 179ROHM SCT2080KEC MOSFET y 40 1200 262ROHM SCT2120AFC MOSFET y 29 650 165ROHM SCT2160KEC MOSFET y 22 1200 165ROHM SCT2280KEC MOSFET y 14 1200 108ROHM SCT2450KEC MOSFET y 10 1200 85STMicroelectronics SCT30N120 MOSFET y 40 1200 270

Manufacturer Model_No Device_TypeHave

in-house?Current Rating (A)

Voltage Rating (V)

Power Rating (W)

Forward Voltage

Cree C2D05120A Schottky Diode y 5 1200 1.8Cree C2D10120A Schottky Diode y 10 1200 1.8Cree C2M0160120D Bodydiode y na na 3.3Cree C2M1000170D Bodydiode y na naCree C3D02060A Schottky Diode y 2 600 1.7Cree C3D02060F Schottky Diode y 4 600 1.7Cree C3D03060A Schottky Diode y 3 600 1.7Cree C3D03060F Schottky Diode y 3 600 1.7Cree C3D04060A Schottky Diode y 4 600 1.8Cree C3D04060F Schottky Diode y 4 600 1.7Cree C3D04065A Schottky Diode y 4 650 1.8Cree C3D06060A Schottky Diode y 5 600 1.8Cree C3D06060F Schottky Diode y 5 600 1.8Cree C3D06065A Schottky Diode y 5 650 1.8Cree C3D08060A Schottky Diode y 8 600 1.8Cree C3D08065A Schottky Diode y 8 650 1.8Cree C3D08065I Schottky Diode y 8 650 1.8Cree C3D10060A Schottky Diode y 10 600 1.8Cree C3D10065A Schottky Diode y 10 650 1.8Cree C3D10065I Schottky Diode y 10 650Cree C3D10170H Schottky Diode y 14.4 1700 2Cree C3D25170H Schottky Diode y 26.3 1700 2.5Cree C4D02120A Schottky Diode y 2 1200 1.8Cree C4D05120A Schottky Diode y 8.2 1200 1.8Cree C4D08120A Schottky Diode y 8 1200 1.8Cree C4D10120A Schottky Diode y 10 1200 1.8Cree C4D15120A Schottky Diode y 10 1200 1.8Cree C4D20120A Schottky Diode y 20 1200 1.8Cree C4D20120A Schottky Diode y 25.5 1200 242 1.8Cree C5D50065D Schottky Diode y 100 650 1.8Cree CMF10120D Bodydiode y na na 3.5Cree CSD01060A Schottky Diode y 2.2 600 1.8

CoolSPICE – SiC will include a library for all commercially important SiC components.

Exhaustive library for SiC components!

3kW DC-DC Converter Design and Development

Prototype a medium power DC-DC converter to:– Provide a test bed for electrical and thermal model verification– Compare and contrast simulation results with measurements in real-world application– Build capability for designing power circuits using Silicon Carbide

Specifications:• Power: 3kW• Vin: 300V. Vout:600V• Switching frequency:

100kHz to 500kHz• Power devices: Silicon

Carbide MOSFETs and Schottky Diodes

• Architecture: Hard switched boost converter

3kW OperationR-C Snubber

Hall effect sensors for current sensingSwappable inductors for testing operation at different frequencies

Lumped Thermal Simulations

Objectives: 1. To provide quick thermal design

and modeling2. To provide a datasheet driven

thermal analysis capability3. To enable back-of-the-envelope

type calculations4. To provide insight into thermal

designs

Methodology:1. CoolSPICE – Thermal libraries2. CoolSPICE – Thermal simulations

Thermal ComponentsTypical components: Conductive, convective, radiative thermal resistors,

thermal capacitors, heat sources, probes, ambients …

Example: Thermal Resistance of a Multi-Wall Heat Sink

• Thermal Resistance of Multi-fin Vertical Heat Sink

• f(Ta,Tw) = {-2e-5 x [(Ta+Tw)/2]2 - 0.0061 x [(Ta+Tw)/2] + 8.3592} x 10-4

• hc-verticalwall_air = 0.59 x f(Ta,Tw) x [(Tw – Ta)/H]0.25 Watts/degC-cm2,

Rc = 1/hc x A

A is the area of all the wallsA = Aout + AinAout = 2H(L+tbp)Ain = 2HL(N-1) + HW

N = number of finsH = height of wallsL = Length of wallsW = Width of back walltbp = Thickness of back plate

Example: Thermal Circuit

Example: Thermal Circuit

Steady state

Transient

Distributed Thermal Simulations

Objectives: 1. To guide thermal design and

modeling and verify simulations 2. To obtain equivalent thermal

resistance networks for electronic circuits and assemblies

𝑅𝑅𝑡𝑡𝑡 = ∆𝑇𝑇𝑄𝑄

[℃𝑊𝑊

]

Methodology:1. 3-D CAD Modeling2. Mesh generation3. Finite-element method thermal

simulation

Typical Components

Typical components:1. Printed circuit board 2. Power semiconductor

devices or modules3. Passive devices

Mesh Generation1. Fuse same-material bodies sharing surfaces2. Create a partition to prevent mesh conflicts 3. Create “volume groups” of bodies sharing material properties and of heat sources4. Create “face groups” of surfaces to assign individual boundary conditions5. Mesh generator assigns mesh elements to volume/face groups

Thermal Simulation: Inverter on a PCB• Simulation of an

inverter board:– Four active

components & a resistor dissipating power

– Natural convection described by heat transfer coefficients on all surfaces

Thermal Simulation: 300W Power Converter

CAD drawing Mesh generated by the CAD tool

“Bodies” in the thermal solver “Boundaries” in the thermal solver

Thermal solver calculated temperature profile

Thermal Simulations with Airflow and Active Cooling

Forced convection: Modeled by • Specifying air flow rate• Solving the Navier-Stokes equation coupled with the heat flow equation

Thermal Simulation: Silicon Carbide Power Module

Module design is from: D. Urciuoli, R. Wood, T. Salem, and G. Ovrebo, “Design and Development of a 400 A, All Silicon-Carbide Power Module” RDECOM presentation

Drawn and meshed in-house at CoolCAD:

12 Diodes16 MOSFETs291000 Nodes1236000 Volume Elements

Thermal Simulation:Silicon Carbide Power Module

CoolCAD calculations: Same geometry, different ambient conditions

TOP:Temperature rise above ambient with aggressive cooling. All dies consume 75W.BOTTOM: Temperature rise above ambient with moderate cooling. MOS dies consume

125W, diodes 75W.

Simulation result from: D. Urciuoli, R. Wood, T. Salem, and G. Ovrebo, “Design

and Development of a 400 A, All Silicon-Carbide Power Module” RDECOM

presentation

Thermal Simulation:Details of the Module Structure

Hierarchical drawing, fusing, partitioning and meshing steps and methods are similar to modeling a circuit on a PCB.

Brief Explanation of Neutron Effects in SiC Power MOSFETs

Earth Radii

Trapped Proton Belt

4

ABB report on “Failure Rates of HiPak Modules Due to Cosmic Rays”

High energy neutron flux as a function of altitude.

High Energy Neutrons Create High EnergyKnock-On Atoms in SiC Devices

Knock-on atoms in SiC due to atmospheric neutrons

Typical Curves After Failure

Measured Cross Sections and FITs

Example failure calculation: FIT@1400 ~103, <104

# of failed devices@1400 using 100 devices => 102 devices x (103 - 104) fails / 109 hours =

on average 0.1 - 1 device out of 100 will fail in 1000 hours

CoolCAD Silicon Carbide Integrated Circuit Fabrication (MOSFETs, JFETs, Diodes, Resistors)

• Layout Design based on custom process rules.• Process Design Kit development for various processes• Lithography mask designs and fabrication• Complementary electrical simulation tools

development: CoolSPICE.

• Silicon carbide, silicon, germanium, etc. fabrication at the Univ. of Maryland’s Maryland Nanocenter FabLab.

• Silicon carbide high temperature complementary processing at CoolCAD’s facility.• Silicon carbide in-house developed recipes for dopant activation, oxidation, etching,

metal deposition, contact annealing, etc.• Silicon carbide Integrated Circuit components fabrication.

Preliminary Data: Dry Ox, no POA W

/L =

200

/100

Typical mueff curves for dry ox dies

Preliminary Data: Nitrous OxideW

/L =

20/

10

mueff curves for dry ox + N2O POA dies

CoolCAD Silicon Carbide Characterization(Electrical, Optical, Radiation)

• Layout and lithography mask design based on custom process rules

• Silicon carbide, fabrication at the Univ. of Maryland’s Maryland Nanocenter FabLab.• Silicon carbide high temperature complementary processing at CoolCAD’s facility.• Silicon carbide recipes for dopant activation, oxidation, etching, metal deposition,

contact annealing, etc.• Silicon carbide sensors fabrication.

Extremely low leakage for large sensors ~4.6 square millimeters

CoolCAD UV Sensor

Competition

Response >10x

CoolCAD’s sensor technology provides superior performance