a geant4 example to predict: radiation effects on components ana keating lip & esa
Post on 19-Dec-2015
233 views
TRANSCRIPT
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
3rd March 2005 Geant4 Tutorial for Space Industry3
Overview
Simple device example Device description Geometry and Materials Physics and cuts Results Different cuts: comparisons
Real device application Device description Results
Conclusions
3rd March 2005 Geant4 Tutorial for Space Industry4
Simple Device Example
Package Lid Substrate
Field Oxide
Sensitive areainside FO
http://geant4.esa.int/repository/EEECExample/
3rd March 2005 Geant4 Tutorial for Space Industry5
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
3rd March 2005 Geant4 Tutorial for Space Industry6
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
3rd March 2005 Geant4 Tutorial for Space Industry7
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);
3rd March 2005 Geant4 Tutorial for Space Industry8
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);
3rd March 2005 Geant4 Tutorial for Space Industry9
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);
3rd March 2005 Geant4 Tutorial for Space Industry10
Sensitive volume
Set GO to sensitive detector:
In EEECDetectorConstruction::Construct()
gateoxide = new EEECGateOxide(SDname="/gateoxide");
SDman->AddNewDetector(gateoxide); logicalGO->SetSensitiveDetector(gateoxide);
3rd March 2005 Geant4 Tutorial for Space Industry11
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
3rd March 2005 Geant4 Tutorial for Space Industry12
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"));
3rd March 2005 Geant4 Tutorial for Space Industry13
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
3rd March 2005 Geant4 Tutorial for Space Industry14
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);
}
3rd March 2005 Geant4 Tutorial for Space Industry15
Data Analysis : example beam
For 105 incident protons of 100 MeV Source point Mono-directional beam Perpendicular to the component surface
Proton 10MeV
3rd March 2005 Geant4 Tutorial for Space Industry16
Hits Position in Gate Oxide
– Source BeamHit —> Impact Point
Gate Oxide
Gate
proton
3rd March 2005 Geant4 Tutorial for Space Industry17
Kind of Particles Hitting the Gate Oxide
Protons : around 94 x103 primary protons + secondary protons Electrons : ~ 10 x103
Positron : one! Light ions : ~ 10
3rd March 2005 Geant4 Tutorial for Space Industry18
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!
3rd March 2005 Geant4 Tutorial for Space Industry19
Ionising Dose in Gate Oxide
Total Ionising Dose deposited by all particles incident on the Gate Oxide
Note: #events Fluence
3rd March 2005 Geant4 Tutorial for Space Industry20
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
3rd March 2005 Geant4 Tutorial for Space Industry21
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
3rd March 2005 Geant4 Tutorial for Space Industry23
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)
3rd March 2005 Geant4 Tutorial for Space Industry24
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 :
3rd March 2005 Geant4 Tutorial for Space Industry25
Packaging: Simulation vs.
Experiments300MeV
Simulation difference bt LID & NOLID 11%
Experimental: 18%
60MeV
Simulation difference bt LID & NOLID 10 %
Experimental: 30%
3rd March 2005 Geant4 Tutorial for Space Industry26
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!
3rd March 2005 Geant4 Tutorial for Space Industry27
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.
3rd March 2005 Geant4 Tutorial for Space Industry28
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.