A Geant4 example to predict: Radiation effects on Components Ana Keating LIP & ESA

A Geant4 example to predict: Radiation effects on Components

Ana Keating

LIP & ESA

http://geant4.esa.int/repository/EEECExample/

3rd March 2005 Geant4 Tutorial for Space Industry2

Aim

Illustrating how to build a Geant4 application on a simple field-effect transistor;

Introducing important features for nanodevices in space.

Simulation goal:

Calculating ionising dose deposited in gate oxide

Check packaging contribution


Overview

Simple device example Device description Geometry and Materials Physics and cuts Results Different cuts: comparisons

Real device application Device description Results

Conclusions


Simple Device Example

Package Lid Substrate

Field Oxide

Sensitive areainside FO

http://geant4.esa.int/repository/EEECExample/


Overview of G4 classes

EEEC D etectorC onstructionG e o m e try an d M ate ria ls

S e ns it ive V o lu m eR e g io ns

EEEC PhysicsListP h ys ic P ro ce sses

D e fa u lt C u tsC u ts p e r re g ion

EEEC Prim aryG eneratorActionG e n era te s P a rtic le A c tion

K in d , E ne rg y, S o urce , B e am ...G 4 G en e ra lP a rtic le S o u rce

G 4 R un M an a g er

EEEC .ccM a in

EEEC G ateO xideco lle c t h its

E n e rg y, pa rt ic le , T iD

EEEC G ateO xideH it

EEEC EventActionH its C o lle c tion

S e t H itog ram in g a nd tup les

EEEC AnalysisM anagerD a ta A n a lys is

If G 4 A N A L YS IS _ U S E =1

EEEC VisM anagerV isu a liza tion

If G 4 V IS _ U S E =1

Mandatory

Optional


Geometry (WIRED/Dawn schemes)

Source

Drain

Gate Oxide

Gate

Lid = 250 mFO = 1.5 mGate = 0.5 mGO = 0.4 mSD = 1.4 mSubstrate = 500 m

Cross Sections

Field Oxide

Gate Oxide > Sensitive Volume


Materials

World Air = new G4Material("Air", 1.290*mg/cm3, 2); Air->AddElement(elN,0.7); Air->AddElement(elO,0.3);

Package Lid PackageLidMat=new G4Material("PackageLidMat",9.*g/cm3,2); PackageLidMat->AddElement(elNi,0.5); PackageLidMat->AddElement(elFe,0.5);

Substrate SubstrateMat= new G4Material("SubstrateMat",2.3*g/cm3,1); SubstrateMat->AddElement(elSi,1);

Field Oxide FieldOxideMat = new G4Material("FieldOxideMat",2.2*g/cm3,2); FieldOxideMat->AddElement(elSi,1); FieldOxideMat->AddElement(elO ,1);


Materials

Source Drain DSMat = new G4Material(name="DSMat", 2.7*g/cm3,1); DSMat->AddElement(elAl,1);

Gate Oxide GateOxideMat = new G4Material("GateOxideMat", 2.3*g/cm3,2); GateOxideMat->AddElement(elSi,1); GateOxideMat->AddElement(elO ,2);

Gate GateMat = new G4Material("GateMat", 2.7*g/cm3,1); GateMat->AddElement(elAl,1);


Construct Layers//EEEC Field Oxide G4Box* FOLayer= new G4Box("FOLayer",ChipLW,ChipLW,FOLCS);

G4LogicalVolume* logicalFOLayer;

logicalFOLayer= new G4LogicalVolume(FOLayer,FieldOxideMat,"FOLayer_L",0,0,0);

G4VPhysicalVolume* physicalFOLayer =

new G4PVPlacement(0,G4ThreeVector(0.*mm,0.*mm,ChipCS-2*PckLidCS-FOLCS),

"FOLayer_P",logicalFOLayer,physicalWorld,false,0);

//EEEC Gate Oxide G4Box* GO= new G4Box("GO",GOW,GOL,GOCS);

G4LogicalVolume* logicalGO;

logicalGO= new G4LogicalVolume(GO,GateOxideMat,"GO_L", 0, 0, 0);

G4VPhysicalVolume* physicalGO =

new G4PVPlacement(0,G4ThreeVector(0.*mm,0.*mm,0.*mm),

"GO_P",logicalGO,physicalFOLayer,false,0);


Sensitive volume

Set GO to sensitive detector:

In EEECDetectorConstruction::Construct()

gateoxide = new EEECGateOxide(SDname="/gateoxide");

SDman->AddNewDetector(gateoxide); logicalGO->SetSensitiveDetector(gateoxide);


Sensitive volume

In EEECEventAction::EEECEventAction(),EEECGateOxideHit* aHit = new EEECGateOxideHit();

aHit->SetWorldPos(worldPos);

aHit->SetLocalPos(localPos);

aHit->SetEnergy(KinE);

aHit->SetPCharge(charge);

aHit->SetPNamef(pNameflag);

aHit->SetTrackId(tracID);

if(tracID!=1)

{aHit->SetVertexVol(SVVolflag);}

hitsCollection->insert(aHit);

// add energy deposition

aHit->AddEdep(edep);

Collecting information on:

Position,

Energy,

Charge Number,

Particle Name,

Track ID

Layer where secondary particles are generated

Ionising energy deposited


Physics List

// General Physics

RegisterPhysics( new EEECGeneralPhysics("general") );

// Electromagnetic Physics

RegisterPhysics( new EEECEMPhysics("Low EM"));

// Hadron Physics

RegisterPhysics( new EEECHadronPhysics("hadron"));

// Ion Physics

RegisterPhysics( new EEECIonPhysics("ion"));


Cuts per region

The cuts define the range from which secondary particles will be tracked as particles or just considered as deposited energy;

Nano-components have very thin sensitive layers;

Source-Drain, Gate, Gate Oxide and Field Oxide have much lower cuts than Package Lid, Substrate and World volume— Source-Drain

— Gate

— Gate Oxide

— Field Oxide

— Secondary particle

o Ionising energy deposition


Cuts Implementation

// Default cut value for World, Package lid and substrate defaultCutValue = 0.5*mm;

// Production thresholds for component regions G4String regName[] = {"R-GO","R-DS","R-FO“, “R-G”}; G4double fusec; for(G4int i=0;i<4;i++) { fusec *= 0.001; G4Region* reg = G4RegionStore::GetInstance()-

>GetRegion(regName[i]); G4ProductionCuts* cuts = new G4ProductionCuts; cuts->SetProductionCut(defaultCutValue*fusec); reg->SetProductionCuts(cuts);

}


Data Analysis : example beam

For 105 incident protons of 100 MeV Source point Mono-directional beam Perpendicular to the component surface

Proton 10MeV


Hits Position in Gate Oxide

– Source BeamHit —> Impact Point

Gate Oxide

Gate

proton


Kind of Particles Hitting the Gate Oxide

Protons : around 94 x103 primary protons + secondary protons Electrons : ~ 10 x103

Positron : one! Light ions : ~ 10


Packaging importance

Major contributors :

Gate Oxide

Gate

Field Oxide

Backscattering :

Substrate

The lack of contribution from the source and drain is merely due to the beam direction!


Ionising Dose in Gate Oxide

Total Ionising Dose deposited by all particles incident on the Gate Oxide

Note: #events Fluence


In case cuts = 0.5 mm (default):

Just secondaries with long penetration depth are considered;

Short range secondaries will only contribute to ionising energy deposition in the layer of creation;

Fewer secondaries reach the Gate Oxide

Check Cuts per region


Total Ionising Dose for different cuts

Real Device Application

Space Users Forum 2003, ESTEC

http://www.estec.esa.nl/wmwww/WMA/EMA_Events/g4spaceusers2003/presentations/GEANT4_AKeating_22012003.pdf


Device Description The NMRC RadFET die consist of four RadFET Sensitive Detector: Only RadfFET1’ Gate Oxide Considered

Radfet #2Radfet #4

Radfet #1#3

S300/50G300/50 D300/50

D690/15

DG300/50

G690/15

S690/15

DG690/15

Bulk

Bulk

Diode

6 Package layers: 250 m lid (1) made of Kovar, adhesive(5),

attach pad(6) and the base (7)


Secondary particles and Packaging

1- Are mostly due to :

Electrons

Protons

2- Depend on Packaging configuration :

As for the simple example in previous slides, Dose Effects :


Packaging: Simulation vs.

Experiments300MeV

Simulation difference bt LID & NOLID 11%

Experimental: 18%

60MeV

Simulation difference bt LID & NOLID 10 %

Experimental: 30%


Conclusions I

This Presentation shows how a simple EEE component can be constructed by following the Geometry construction procedures of the first example presented here consisting of:

3 packaging layers;

A gate oxide as sensitive volume;

A gate, a source and a drain.

It is available in: http://geant4.esa.int/repository/EEECExample/

Do not forget README file!


Conclusions II

The example included Cuts per region

Physics list consists of: general physics,

decay,

low energy electromagnetic physics,

as well as ions, proton (anti-proton), neutron (anti-neutron) elastic and

inelastic processes.

Calculation of Total ionising Dose deposited in the gate oxide.


Conclusions III

The example presented also illustrates how :

AIDA analysis creates histograms and tuples

Deposited energy, Type of particles hitting the gate oxide,

Layer where secondary particles are generated,

Energy of incident particles,

Total ionising dose deposited in the gate oxide.

A Geant4 example to predict: Radiation effects on Components Ana Keating LIP & ESA

Documents

space industry

2005geant4 tutorial

new g4materialname

new g4materialair

new g4materialpackagelidmat

new g4materialfieldoxidemat

new g4materialgateoxidemat

new g4materialsubstratemat