PN Junction DiodeIV Characteristics, Carrier Profiles

Diode IV

1. PN Junction Simulation Presented by Pradeep Verma Under guidance Prof. Satyendra K. Mourya

2. Device Structure and Mesh

3. SDE Command ;Dimension of p type ( sdegeo:create-rectangle (position 0 0 0)  (position 0.5 1 0) "Silicon" " p_regoin ") ;Dimension of n type ( sdegeo:create-rectangle (position 0.5 0 0)  (position 1 1 0) "Silicon" " n_region ") ;Doping of p type ( sdedr:define-constant-profile " p_r " " BoronActiveConcentration " 1e+17) ( sdedr:define-constant-profile-region "p_r_profile_1" " p_r " " p_regoin ") ;Doping of n type ( sdedr:define-constant-profile " n_r " " PhosphorusActiveConcentration " 1e+17) ( sdedr:define-constant-profile-region "n_r_profile_1" " n_r " " n_region ") ;Set Contact ( sdegeo:define-contact-set "anode" 4  ( color:rgb 1 0 0 ) "##") ( sdegeo:define-contact-set "cathode" 4  ( color:rgb 1 0 1 ) "##") ( sdegeo:set-current-contact-set "anode") "none" ( sdegeo:set-contact (list (car (find-edge-id (position 0 0.5 0)))) "anode") ( sdegeo:set-current-contact-set "cathode") "anode" ( sdegeo:set-contact (list (car (find-edge-id (position 1 0.5 0)))) "cathode") ;Mesh for Whole ( sdedr:define-refeval-window "RefEvalWin_1" "Rectangle"  (position -0.0625 -0.1184 0) (position 1.0818 1.1249 0)) ( sdedr:define-refinement-size "RefinementDefinition_1" 0.1 0.1 0.01 0.01 ) ( sdedr:define-refinement-placement "RefinementPlacement_1" "RefinementDefinition_1" (list "window" "RefEvalWin_1" ) ) ;Mesh for Junction ( sdedr:define-refeval-window "RefEvalWin_2" "Rectangle"  (position 0.3 -0.1 0) (position 0.7 1.1 0)) ( sdedr:define-refinement-size "RefinementDefinition_2" 0.01 0.01 0.001 0.001 ) ( sdedr:define-refinement-placement "RefinementPlacement_2" "RefinementDefinition_2" (list "window" "RefEvalWin_2" ) ) ( sde:set-meshing-command " snmesh ") ( sde:build-mesh "" " sdemodel ") "Meshing successful" ( system:command " svisual sdemodel_msh.tdr &") ( sde:build-mesh " n@node @")

4. Sdevice Command File { * Input Files Grid= " sdemodel_msh.tdr " * Output Files    Plot      = "@ tdrdat @"    Current   = "@plot@"    Output    = "@log@" } Electrode { { Name= "anode" Voltage= 0.0 } { Name= "cathode" Voltage= 0.0 } } Physics { Fermi Recombination ( SRH( DopingDependence TempDependence ) Auger Avalanche ) eMobility ( DopingDependence HighFieldSaturation Enormal ) hMobility ( DopingDependence HighFieldSaturation Enormal ) } Plot { *--Density and Currents, etc eDensity hDensity TotalCurrent /Vector eCurrent /Vector hCurrent /Vector Current eMobility hMobility eVelocity hVelocity eLifetime hLifetime eDriftVelocity *--Fields and charges ElectricField /Vector eEffectiveField Potential SpaceCharge *--Doping Profiles Doping TotalConcentration DonorConcentration AcceptorConcentration eEquilibriumDensity hEquilibriumDensity *--Generation/Recombination SRHRecombination eSRHRecombination hSRHRecombination SurfaceRecombination Band2Band Auger eAvalanche hAvalanche *--Band structure/Composition ConductionBand ValenceBand CurrentPotential eVelocity hVelocity hDriftVelocity eDriftVelocity } Math { Number_of_Threads =4 Extrapolate Notdamped = 50 Iterations= 20 RHSmax = 1e50 RHSFactor = 1e10 ExitOnFailure } Solve { Coupled ( Iterations=200 LineSearchDamping =1e-8 ){ Poisson } Coupled ( Iterations=200 LineSearchDamping =1e-8 ){ Poisson Hole Electron } Save ( FilePrefix ="Initialized" ) Quasistationary ( InitialStep = 0.001 Increment= 1.3 Decrement=2 MinStep = 1e-5 MaxStep = 0.01 Goal {Name= "anode" Voltage=1} ) { Coupled { Poisson Electron Hole} Plot( FilePrefix ="PN" NoOverWrite Time=(Range=(0 1) Intervals=4) # saves  the structure at this interval ) } }

5. Formula   Poisson’s equation Transport Equations Continuity equations  

6. Energy band diagram at 0 V Where Vt = kT/q     Maximum Field =113.0048 KV/cm Built-in Voltage=0.8399 V Band Gap=1.12 eV Depletion Width=0.1487 micron Depletion Capacitance= 70.882 nanoFarads /cm^2

7. Energy band diagram at 0.8 V Where Vt = kT/q Here Va = 0.8 V   =   =   =   =  

8. Electron and Hole Density Plot

9. Space Charge

10. Electric Field

11. IV of Diode  

12. IV of GaN and Si based Diode

13. Thank You