TCAD Simulation for Organic and Polymer Devices 9/5/06

Transcription

1 TCAD Simulation for Organic and Polymer Devices 9/5/06

2 TCAD Simulation for Organic Devices Physical Models for analysis of electrical characteristics for Organic devices Optical Approach by TCAD to Organic LED for Electroluminescence TCAD solution for designing of AM-OLED OTFT / OLED example a-tft, Poly-TFT / OLED example a-tft, Poly-TFT (RPI Model) / OLED example - 2 -

3 Simulation for Organic Devices: TCAD Simulation Software ATHENA Framework: Process Simulation ATLAS Framework: Device Simulation S-PISCES: Silicon Device Simulator TFT: module for a-tft/ Poly-TFT Combination for the Organic Device Simulation BLAZE: Core Device Simulator for the compound materials OTFT: Module for the Organic materials OLED: Module for the OLED simulation, Output Coupling by Ray-Tracing Giga: Module for the Self-Heating MixedMode: Simulation for the Device-Circuit mixed Deckbuild : Runtime Software DOE Simulation Devedit : GUI Structure Software Tonyplot : Visual Software Optimizer : Optimization Software - 3 -

4 Simulation for Organic Devices: TCAD Simulation Software Method of making structure ATHENA/Devedit Devedit : GUI Structure Software OLED OTFT OTFT Deckbuild : Runtime Software DOE Simulation Tonyplot : Visual Software Optimizer : Optimization Software - 4 -

5 TCAD Simulation for Organic Devices Physical Models for analysis of electrical characteristics for Organic devices Optical Approach by TCAD to Organic LED for Electroluminescence TCAD solution for designing of AM-OLED OTFT / OLED example a-tft, Poly-TFT / OLED example a-tft, Poly-TFT (RPI Model) / OLED example - 5 -

6 Physical Models for Analysis of Electrical Characteristics for Organic Devices Periodic Lattice Amorphous Lattice Delocalized charges Localized charges Crystals: Periodic structures Band Model (Conduction Band, Valence Band) Delocalized charges (electrons in CB, holes in VB) Amorphous organic materials: Band Model Localized charges (radical ions) Transport through intersite Hopping Charge Traps (DEFECTS) - 6 -

7 TCAD Simulation for Organic Devices Physical Models for analysis of electrical characteristics for Organic Devices Organic Transport Defect Density of States Hopping Model Effective Transport Energy Hopping Mobility Basic Transport Equations Poole-Frenkel Mobility Langevin Recombination - 7 -

8 Physical Models for Analysis of Electrical Characteristics for Organic Devices Defect Density of States Compound Material Amorphous DOS Crystal BandTail Organic Ev Ec Ev Ec Localized defect of density Ev Ec - 8 -

9 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport Defect Density of States DOS with Characteristics temperature and Trap Density g g A D ( E) = H kt H kt A CA Ê E - E exp Á Ë ktca ˆ D v ( E) = expá CD c Ê E - E Á Ë ktcd ˆ Ev Ec - 9 -

10 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport Defect Density of States n Trapped Carrier Density p A D = = E c Ú E v E c Ú E v g g A ( E) f ( E, n, p) D ta ( E) f ( E, n, p) td de de f ta (E,n,p) :Acceptor probability of occupation f td (E,n,p) : Donor probability of occupation Steady-State, Transient Recombination

11 Physical Models for Analysis of Electrical Characteristics for Organic Devices Hopping Model Variable-range hopping is the dominant transport mechanism due to strong charge localization Carrier hopping occurs at shallow state energies This is the Effective Transport Energy Trap DOS is modeled by a double peak Gaussian distribution

12 Physical Models for Analysis of Electrical Characteristics for Organic Devices Concept of the Hopping Transport Et ft r Est r r ft Et ft Et Carrier jump rate from a starting site of energy Est to a target site of energy Et over the distance r is often described by the Miller-Abrahams expression Downward hopping Ï1, Et < Est Ô v ( Est, Et, r) = v0 exp( - 2gr) Ì Ê Et - Est ˆ, Et > Est exp Ô Á- Ó Ë kt tunneling Upward hopping

13 Physical Models for Analysis of Electrical Characteristics for Organic Devices Hopping Model Effective Transport Energy The effective carrier transport energy (Etr) is calculated from 1,2 : Energy Ed Density of state s d s i Traps Ni Intrinsic DOS LUMO/HOMO Nd E tr g Ú - g( E) 3 ( E)( Etr - E) de = ( gkt N Ê - E exp Á Ë 2s i ˆ + 6b p ( E E ) Ê - + expá Ë 2s 2 = i d d 2 2ps 2 2 i ps d d N ) 3 2 ˆ Where g(e) is the DOS distribution, N i is the total intrinsic state density, N d is the total dopant state density, s i is the intrinsic Gaussian DOS width, s d is the dopant Gaussian DOS width, E d is the energy shift, g is 1/carrier localization radius, b is the percolation constant, E is the band energy, k is Boltzmann s constant and T is the lattice temperature 1 Charge carrier mobility in doped disordered organic semiconductors - V.I. Arkhipov, P. Heremans, E.V. Emelianova, G.J. Adriaenssens, H. Bassler, Journal of Non-Crystalline Solids, , pp , Charge carrier mobility in doped semiconducting polymers - V.I. Arkhipov, P. Heremans, E.V. Emelianova, G.J. Adriaenssens, H. Bassler, Applied Physics Letters, Vol. 82, No. 19, pp ,

14 Physical Models for Analysis of Electrical Characteristics for Organic Devices Hopping Model Hopping Mobility The effective carrier mobility ( D = tr mtr = m v tr tr = r 2 j ed tr kt qn kt È ÍÎ v r j tr = v 0 E Ê = Á Ú tr de g Ë - from Einstein relation g( E) de Ê Á Ê 3b ˆ exp Á - 2Á Ë 4p Ë ˆ ( E) -1 3 È Í Ê 3b ˆ exp - 2Á Í Ë 4p Î ( E) 2 1 E tr 3 E tr Ú - Ú g( E) - de Where g(e) is the DOS distribution, n 0 is the attempt-to-jump frequency, g is 1/carrier localization radius, b is the percolation constant, E is the band energy, q is the electronic charge, k is Boltzmann s constant and T is the lattice temperature m tr 1 3 È g Í ÍÎ ) is calculated from1: E tr Ú - de g g È ÍÎ -1 3 ˆ Charge carrier mobility in doped disordered organic semiconductors - V.I. Arkhipov, P. Heremans, E.V. Emelianova, G.J. Adriaenssens, H. Bassler, Journal of Non-Crystalline Solids, , pp ,

15 Physical Models for Analysis of Electrical Characteristics for Organic Devices Hopping Model Hopping Mobility Ref) Charge carrier mobility in doped semiconducting polymers - V.I. Arkhipov, P. Heremans, E.V. Emelianova, G.J. Adriaenssens, H. Bassler, Applied Physics Letters, Vol. 82, No. 19, pp , Depend on the equilibrium hopping mobility upon the dopant concentration

16 Organic Transport Basic Equation Drift-Diffusion ( ) ( ) p qd E qp J R G div J q t p n qd E qn J R G div J q t n Q N N p n q div p p p p p p p n n n n n n n T A D + = - + = + = - + = = Æ Æ Æ Æ Æ Æ - + m m y e 1 1 Physical Models for Analysis of Electrical Characteristics for Organic Devices

17 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport Poole-Frenkel Mobility Low Field Mobility from Hopping Mobility m m 1 T g PF PF eff ( E) ( E) Ê m0 expá = - Ë kt 0 b = eff Ê m0 expá = - Á Ë kt 1 1 = - T T eff is fitting Parameter q pe e r + Ê + Á Ë 0 E E 0 b kt eff ˆ ˆ -g ˆ E : Activation Energy : Poole-Frankel Factor

18 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport Langevin Recombination R = qnp ee 0 quenching ( m h ( E) + m ( E ) Singlet Exciton Triplet Exciton e Ex) Organic LED, Organic LASER

19 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport Generation : Depend on the exciton dissociation e - hv 3 2 e - LUMO 5 LUMO 1 4 HOMO 3 h + G = ab sun e - a x h ex anode HOMO electron acceptor electron donor cathode Ex) Organic Solar Cell

20 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport J-V characteristics example : Ohmic and SCLC LUMO= ITO PPV Au 5.1 HOMO=

21 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Device Simulation Examples J-V characteristics example : Comparison 3.2 A mu0/10 0 LUMO=3.0 HOMO=5.4 mu0 5.3 Comparison 3.2 B mu0/10 0 LUMO=3.0 HOMO= mu0 C LUMO=3.0 mu0 mu0/100 HOMO=6.0 mu

22 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport : Electron/Hole, Electric Field, Langevin Recombination Rate 3.2 HOMO= A mu0/100 mu0 B mu0/100 LUMO= LUMO=3.0 mu0 5.3 HOMO= C mu0 mu0/100 LUMO=3.0 HOMO=6.0 mu

23 Physical Models for Analysis of Electrical Characteristics for Organic Devices Organic Transport I-V Example Depend on the PPV thickness ITO/MEH-PPV/Cu

24 Physical Models for Analysis of Electrical Characteristics for Organic Devices OTFT Example I-V of Pentacene : p-type Gate L/W=120/600um Gate Source Pentacene Gate dielectric Gate Electrode c-si Sub. Drain

25 TCAD Simulation for Organic Devices Physical Models for analysis of electrical characteristics for Organic devices Optical Approach by TCAD to Organic LED for Electroluminescence TCAD solution for designing of AM-OLED OTFT / OLED example a-tft, Poly-TFT / OLED example a-tft, Poly-TFT (RPI Model) / OLED example

26 TCAD Simulation for Organic Devices Optical Approach by TCAD to Organic LED for Electroluminesence Distribution of the Singlet, Triplet Exciton Output Coupling by ray-tracing Cathode Light 10V DC Anode Organic Material

27 Optical Approach by TCAD to Organic LED for Electroluminescence Concept of the Singlet, Triplet Exciton E Singlet S1 excited sate E Triplet T1 excited sate Singlet S1 excited sate T1 Triplet excited sate FLUORESCENCE S0 ground state S0 ground state PHOSPHORESCENCE singlet exciton trilet exciton Apply Electric Field

28 Optical Approach by TCAD to Organic LED for Electroluminescence Concept quenching of the Singlet, Triplet Exciton S k 1 ISC Annihilation k ST Radiative decay T 1 Non-Radiative decay k Rf k SS k SP Annihilation k Rp k TT k TP Annihilation S 0 k ST k SP k SS k TP k TT k ISC Unit 2e7 4e8 5e8 2e9 1.4e9 0 cm3/s for Tetracene

29 Optical Approach by TCAD to Organic LED for Electroluminescence Rate Equation for Singlet, Triplet Exciton S T ( x, y, t) t ( x, y, t) t = = R st - K Rst rnp + 1+ R SP S st K TT K 2 T 2 - K ISC S - K S t ST SS 2 ( n + p) - S - K S - + ( D S) NRS ( 1- R ) rnp + K S - K T( n + p) - K st NRT T T - t D S : diffusion constant of singlet D T : diffusion constant of triplet R st : Fraction of singlet formed (1/4) r t t S T : Langevin Recombination Rate : singlet exciton lifetime : triplet exciton lifetime T ISC + ( D T) T TP p t ST - K 1 q S TT T 2 Self-consistently solve with drift-diffusion equation n t = = 1 q Æ div J div J n Æ p S + G n + G p - R n - R p

30 Optical Approach by TCAD to Organic LED for Electroluminescence Distribution of Singlet and Triplet Excitons in an OLED Anode Voltage =3 V Singlet Triplet Light Power Rlangevin TPD Alq3-30 -

31 Optical Approach by TCAD to Organic LED for Electroluminescence Bi-layer TPD/Alq3 OLED Example: IL & Internal Efficiency Internal Efficiency = Light power / Input power(v*i) Anode Voltage vs Light Power Anode Voltage vs Internal Efficiency

32 Optical Approach by TCAD to Organic LED for Electroluminescence Distribution of physical values in OLED Distribution of Singlet exciton, Electric Filed and Langevin Recombination rate and Charge 3Layer OLED OLED A

33 Optical Approach by TCAD to Organic LED for Electroluminescence Distribution of physical values in OLED Distribution of Singlet exciton, Electric Filed and Langevin Recombination rate and Charge 3Layer OLED 5.0 OLED B

34 Optical Approach by TCAD to Organic LED for Electroluminescence Comparison of Current-Voltage for 2 OLEDs OLED A OLED B For SCLC behavior J~V 2 log-log scale

35 Optical Approach by TCAD to Organic LED for Electroluminescence Langevin Recombination TPD 3.0 Alq3 3.3 Mg:Ag ITO nm nm Light output will be delayed

36 Optical Approach by TCAD to Organic LED for Electroluminescence Output Coupling for OLED

37 Optical Approach by TCAD to Organic LED for Electroluminescence Output Coupling by Ray-tracing EDGE.ABSORB or EDGE.REFLECT Organic MIR.TOP Depend on Exciton distribution AMBIENT INDEX n* = n i k MIR.BOTTOM Exciton Boundary- to- Boundary Ray-tracing Matrix Method Smoothing Algorithm NFP (Near Field Pattern) FFP(Angular Far Field Pattern) Output Coupling

38 Optical Approach by TCAD to Organic LED for Electroluminescence Output Coupling by Ray-tracing Matrix Method for Ray-Tracing n*=n-ik : complex index Reflectivity Transmissivity Absorption

39 Optical Approach by TCAD to Organic LED for Electroluminescence Conventional OLED TE mode TM mode n=1.5 Photonic Crystal n=1.9 n=1.8 n=

40 Optical Approach by TCAD to Organic LED for Electroluminescence Bottom Emission Super Top Emission

41 TCAD Simulation for Organic Devices Physical Models for analysis of electrical characteristics for Organic devices Optical Approach by TCAD to Organic LED for Electroluminescence TCAD Approach for Designing AM-OLEDs OTFT / OLED example a-tft, Poly-TFT / OLED example a-tft, Poly-TFT (RPI Model) / OLED example

42 TCAD Approach for Designing AM-OLEDs Why TCAD is important for AM-LCD/OLED? AM-LCD SOURCE LINE AM-OLED SOURCE LINE C ST C LC LCD I DS OLED GATE LINE a-si TFT Poly-TFT GATE LINE a-si TFT Poly-TFT Organic TFT Pass a voltage I DS non-uniformity does not matter Drive a current Uniform I DS is critical V th control critical m and V th control critical

43 TCAD Approach for Designing AM-OLEDs OTFT+ OLED Need accurate OTFT and OLED Models

44 TCAD Approach for Designing AM-OLEDs a-tft+oled Vth shift analysis of an a-si:tft dn dn ( x, y, t) dt ( x, y, t) dt s = q E s = q H J J inj, n inj, p ( x, y, t) ( NTA( x, y) - N( x, y, t ) ( x, y, t) ( NTD( x, y) - N( x, y, t ) Gate:+ V Ê ncox ˆÊW ˆ I DS = Á m Á GS - Ë 2 Ë L Drain:+V TFT I DS OLE D 2.0~2. 3 ( V V ) NTA=Acceptorlike trap density at time=0 SIGMAE=capture cross section *Need to calibrate for each a-si:tft device T Degradation depend on stress time

45 TCAD Approach for Designing AM-OLEDs a-tft, Poly-TFT(RPI Model) +OLED LEVEL TFT(a-Si) modified Leroux modified RPI LEVEL TFT(poly-Si) modified UCB modified RPI Multi TFT circuit simulations using Spice or TCAD

46 TCAD Approach for Designing AM-OLEDs UTMOST SmartLib : share with SmartSpice, UTMOST, ATLAS MOS, BJT, TFT, Diode.. Active Device Models SmartSpice

47 TCAD Approach for Designing AM-OLEDs Example the Active device as TCAD.begin 5 Vdd Vselect pulse n 20n 20n 500n 20u 1 Vdata pulse n 20n 20n 19u 40.5u Voled Cam pF atft1 3=drain 5=gate 4=source infile=atft1.str \ width=150e-6 atft2 1=drain 4=gate 2=source infile=atft2.str \ width=200e-6 aoled 2=anode 6=cathode infile=oled.str \ width=200e-6.tran 0.1ns 200us.end

48 TCAD Approach for Designing AM-OLEDs An example of a 3 a-si TFT + OLED Pixel Design (ATLAS/S-PISCES/TFT+BLAZE/OLED+MixedMode) Vselect VDD T1 W 15 L 10 MODEL ATLAS Vdata T1 Cst T2 T3 Iout T ATLAS T ATLAS OLED ATLAS Cst =0.2pF OLED Area 7200 um 2 OLED

49 TCAD Approach for Designing AM-OLEDs An example of a-si TFT + OLED OLED characteristics a-si:tft characteristics

50 TCAD Approach for Designing AM-OLEDs An example of a 3 a-si TFT + OLED pixel design OLED current and Light power 3 a-si:tft + OLED Potential Distribution

51 TCAD Approach for Designing AM-OLEDs LTPS-TFT Simulated transient carrier effects Inverter Circuit 2 Vdd 1 ptft 3 ptft - on Vin Vout ntft C ntft - off

52 TCAD Approach for Designing AM-OLEDs LTPS-TFT TFT Inverter TCAD vs SPICE Comparison of the switch voltage during transient simulation Vin 50% duty Short on long off Long on short off Off-on On-off Off-on On-off TCAD SPICE

53 Example of a 4 LTPS TFT Level Shifter (ATLAS/S-Pisces/TFT+Blaze/OLED+MixedMode) LTPS-TFT TFT Level Shifter in TCAD Vdd Vin T1 T3 RPI TFT Model level36 p-tft Vin Vout T2 T4 Vss n-tft ATLAS

54 Example of a 4 LTPS TFT Level Shifter (ATLAS/S-Pises/TFT+Blaze/OLED+MixedMode) LTPS-TFT TFT Level Shifter in TCAD go atlas.begin vdd vpin pulse n 20n 20n 200n 440n vnin pulse n 20n 20n 200n 440n # ptft- RPI Model mptft ptype L=6U W=54U mptft ptype L=6U W=54U # ntft- ATLAS Device an1 4=drain 5=gate 6=source infile=ntft01.str width=10 an2 5=drain 4=gate 6=source infile=ntft01.str width=10 vss load infile=circuitb.log outfile=cirb11.tran 1n 4630n By UTMOST.MODEL ptype PTFT ( LEVEL = 36 +TNOM = 27 TOX = 8.5E-8 VTO = VFB = VON = 0 DVT = 0 +VKINK = VSI = 2 VST = 2 +MU1 = MMU = 5 MU0 = MK = 1.3 MUS = 0.5 RD = RS = BT = E-6 BLK = E-3 +DD = E-7 DELTA = DG = E-7 +EB = ETA = I0 = I00 = ASAT = AT = E-8 +DASAT = 0 LASAT = 0 LKINK = 1.9E-6 +DVTO = 0 DMU1 = 0 CAPMOD = 0 +CGDO = 200E-12 CGSO = 200E-12 ETAC00 = 6 +MC = 2 RDX = 0 RSX = 0 +VMAX = 1E5 VERSION = 2 ME = 2.5 +META = MSS = 2 THETA = E-10 +ISUBMOD = 1 LAMBDA = LS = 3.5E-8 +VP = 0.2 INTSDNOD= 0 ).end source ntft_model01.in source ntft_model02.in

55 Parasitic Capacitance and Resistance of a Pixel How to extract the parasitic capacitance and resistance of a pixel? 5 Cgate-data Parasitic T1 T2 Rcon PLED VOLED

56 Application of CLEVER for the Parasitic Extraction of a Pixel The original GDS2 layout is loaded into MaskViews and a reduced area is selected for 3D simulation 2D cut-plane through a 3D TFT pixel structure showing potential distribution for an interconnect

57 Application of CLEVER for the Parasitic Extraction of a Pixel The 3D structure is built using 3D process simulation. The field solver simulated inside of the conductors for resistance extraction and within insulators for capacitance extraction. All parasitics are automatically back annotated onto the original extracted SPICE netlist GDS, Process, Map information

58 Extracted Parasitics are Back Annotated into SPICE-netlist M1 int1 int2 int0 GND TFT w=1u l=1u As=8.125p Ad=1.25p Ps= u Pd=4.5u Nrs=0 Nrd=0.5 geo=0 M2 int1 int4 int3 GND TFT w=1u l=1u As=8.125p Ad=1.25p Ps= u Pd=4.5u Nrs=0 Nrd=0.5 geo=0 M3 int1 int6 int5 GND TFT w=1u l=1u As=8.125p Ad=1.25p Ps= u Pd=4.5u Nrs=0 Nrd=0.5 geo=0 M4 int7 int8 int7 GND TFT w=1u l=1u As= p Ad=1.25p Ps= u Pd=4.5u Nrs=8.75 Nrd=0.5 geo=0 M5 int7 int9 int7 GND TFT w=1u l=1u As= p Ad=1.25p Ps= u Pd=4.5u Nrs=8.75 Nrd=0.5 geo=0 M6 int7 int10 int7 GND TFT w=1u l=1u As= p Ad=1.25p Ps= u Pd=4.5u Nrs=8.75 Nrd=0.5 geo=0 M7 int11 int12 int11 GND TFT w=1u l=1u As= p Ad=1.25p Ps= u Pd=4.5u Nrs=8.75 Nrd=0.5 geo=0 M8 int11 gate7 int11 GND TFT w=1u l=1u As= p Ad=1.25p Ps= u Pd=4.5u Nrs=8.75 Nrd=0.5 geo=0 M9 int11 int14 int11 GND TFT w=1u l=1u As= p Ad=1.25p Ps= u Pd=4.5u Nrs=8.75 Nrd=0.5 geo=0 C1 gate7 SL4_ e-15 C10 gate7 ITO_4_3_ e-17 C2 gate7 SL3_ e-15 C11 gate7 ITO_4_2_ e-15 C3 gate7 SL2_ e-15 C12 gate7 COM_ e-14 C4 gate7 PG1_B_ e-16 C13 gate7 ITO_1_4_ e-18 C5 gate7 PG3_ e-16 C14 gate7 ITO_2_4_ e-18 C6 gate7 PG2_B_ e-15 C15 gate7 ITO_4_1_ e-17 C7 gate7 ITO_3_ e-15 C16 gate7 ITO_3_4_ e-18 C8 gate7 PG3_B_ e-18 C17 gate7 ITO_4_4_ e-18 C9 gate7 GND e

59 Summary of TCAD Approach to AM-OLED Design ATLAS for Organic Device and AM-OLED/LCD New Hopping Transport Model Organic Transport DOS Trap Density OTFT, OLED Examples Singlet, Triplet Exciton Generation and Quenching Extract the Output Coupling for OLED Mixed Simulation with Device and Circuit for AM-OLED Parasitics Extraction using CLEVER