Modeling and Reliability investigation with HiCuM for InP ...€¦ · 2/27 Purpose Physics based...
Transcript of Modeling and Reliability investigation with HiCuM for InP ...€¦ · 2/27 Purpose Physics based...
Modeling and Reliability investigation with HiCuM for InP/InGaAs DHBT
S. Ghosh, F. Marc, C. Maneux, B. Grandchamp, G. A. Koné, T. Zimmer.
IMS Lab., University of Bordeaux 1.
11th HICUM Workshop 2011 (28th & 29th June)
IMS Lab., University of Bordeaux 1.
2/27
Purpose
Physics based modeling with high accuracy level (before aging)
Introduction of the InP HBT degradation laws into its compact model
An essential step to achieve built in reliability at circuit level
Implementation of aging circuit in compact electrical model
Impact of device failure mechanisms on the circuit in operating conditions.
3/27
Outline
The InP HBT: some technological aspects
Modeling with HiCuM L2 v2.24G
Summary of accelerated bias aging tests
Physical aging Model using TCAD tools
Electrical aging Model using HiCuM
Enhancement of the HiCuM model L2
Demonstration of the compact model including aging
Device level
Circuit level (Common emitter amplifier)
Conclusion
4/27
InP HBT: technological aspects
Name Material Level (cm-3)
G1
Thickness (nm)
G1
Cont Em In0.53Ga0.47As >1019 100
Emitter 2 InP >1019 180
Emitter 1 InP 2x1017 40
Base InX-1GaXAs 8 x1019 ≈30
Buffer In0.53Ga0.47As 1x1016 30
Collector 2 InP 5x1017 20
Collector 1 InP 2.5x1016 80
Cont Co 3 InP >1019 <100
Cont Co 2 In0.53Ga0.47As >1019 <50
Cont Co 1 InP >1019 350
Etch-Stop In0.53Ga0.47As 10
Contact Co 1
Contact Co 2
Contact Co 3
Collector 1
Emitter 2
Emitter Contact
Emitter 1
Buffer
Collector 2
Base
HBT devices from III-V Lab
InP substrate
GSMBE growth
Self-aligned triple-mesa process
Ti/Au metallization
Polyimide passivation.
5/27
Modeling with HICUM/L2 v2.24G
In advanced HBTs the effective reverse Early voltage decrease drastically with the increasing of RF performances
This small effective reverse Early voltages becomes strongly temperature dependant
The new version of HiCUM model is able to physically solve these problem and has already been demonstrated on SiGe HBT technology
InP DHBT technology faces similar types of problems
This new version* and the similar parameter extraction strategy* has been adopted for the modeling purpose
*Z. Huszka, D. Céli and E. Seebacher, “A Novel Low-Bias Charge Concept for HBT/BJT Models Including Heterobandgap and
Temperature Effects - Part I: Theory , Part II: Implementation, Parameter Extraction and Verification”, IEEE Trans. Electron. Dev., 2011
6/27
HICUM/L2 v2.24G new model equations
Collector current at low current densities
Temperature dependence
001 .
0 0.ETAG
T
G TZ
PP eQQ
01 .
.ETAGEZ
J
G
E E
T
T
J I IH eH
01 .
.ETAGCZ
J
G
C C
T
T
J I IH eH
TTT EEE
TTT CCC
0 0
0
0
1 .
. . ( ) . . ( )
BCBE
T T
VV
V V
C G G G
P JEI P E JCI P C
e e
IQ H Q T H Q T
C
7/27
Preliminary assumption of parameter values: ZEDC=0.999 and AJEDC=10
)(/1ln 0TVV DEDCBE
Extracted Parameters: IS, HJEI, VDEDC
Parameter Extraction Results (0.7x10 µm2) (1/2)
0.0E+00
2.0E+14
4.0E+14
6.0E+14
8.0E+14
1.0E+15
1.2E+15
1.4E+15
-2 -1.5 -1 -0.5 0
-HJEI/IS
1/IS
1A
BE
TV
V
Ce
I
8/27
Parameter Extraction Results (0.7x10 µm2) (2/2)
Extraction of QP0 Parameter
Optimization of parameters IS, HJEI, VDEDC, AJEDC and QP0
QP0 Extraction
IS, HJEI
VDEDC, AJEDC
and QP0
0,4 0,6 0,8 1,00,0
0,5
1,0
1,5
Temp = 27 OCI C
/eV
BE/(
Mcf*V
T) (
fA)
VBE
(V)
Meas
Sim
9/27
Normalized collector current
Impact of the temperature on the effective reverse early effect
Accuracy of temperature dependant parameters: ZETAG0, ZETAGE, ZETAGC, ZETACT, VGB, DELTE, DELTC
0.4 0.6 0.8 1.00
10
20
Temp = 50 OC
I C/e
Vb
e/(
MC
F*V
T) (f
A)
V BE
(V)
Meas
Sim
0.4 0.6 0.8 1.00
200
400
I C/e
Vb
e/(
MC
F*V
T) (f
A)
VBE
(V)
Meas
Sim
Temp = 80 OC
0.4 0.6 0.8 1.00.0
0.5
1.0
1.5
Temp = 27 OC
I C/e
Vb
e/(
MC
F*V
T) (
fA)
VBE
(V)
Meas
Sim
10/27
Fwd Gummel plots and Collector Current at different VCB
0.4 0.6 0.8 1.01E-9
1E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
I C (
A)
VBE
(V)
IC.M_27OC
IC.S_27OC
IC.M_50OC
IC.M_50OC
IC.M_80OC
IC.M_80OC
VBC
= 0
0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94 0.96
0.00
0.01
0.02
0.03
0.04
0.05
I C (
A)
VBE
(V)
Meas
Sim
VCE
= 0.8 to 1.2 V
@ 0.1V Steps
Temp= 27OC
11/27
Output and fT characteristics
-0.5 0.0 0.5 1.0 1.5 2.0
0
3
6
9
12
15
18
I C
(mA
)
VCE
(V)
Meas
Sim
IB sweep
100uA to 700uA
1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0,01 0,1 10
50
100
150
200
250
300
350
f T (
GH
z)
IC (A)
Meas
Sim
VBC
=0
0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,10
50
100
150
200
250
300
350
VBC
=0
f T (
GH
z)
VBE
(V)
Meas
Sim
12/27
Summary of Extraction results
Easier C10, QP0, HJEI extraction for HICUM/L2 (Convenient for single geometry parameter extraction procedure)
Unified approach between HL0 and HL2
Modeling of the reverse early effect
Temperature dependence of reverse early effect
Parameter extraction and validation on InP HBT technology at wide range of temperatures, from low to high current densities and in DC and AC conditions
13/27
Current density and bias stress conditions
Bias Point #1: (not used)
Vce : 1.5V
Jc: 400KA/cm²
Aging Temperature 30°C
Bias Point #2:
Vce : 2V
Jc : 400 KA/cm²
Aging Temperature 30°C
Tj = 100°C (T7)
Bias Point #3:
Vce : 2.5V
Jc : 400 KA/cm²
Aging Temperature 30°C
Bias Point #4:
Vce : 2.7V
Jc : 400 KA/cm²
Aging Temperature 30°C
Bias Point #2’:
Vce : 1.31V
Jc : 610 KA/cm²
Aging Temperature 30°C
Tj = 100°C (T7)
0.0 0.5 1.0 1.5 2.0 2.5 3.0
0
200
400
600
125°C118°C
100°C
83°C
P2'
P4P3P2
100µA <IB< 800µA step size 100µA
T7
JC (
KA
/cm
²)
VCE
(V)
P1
14/27
Results of accelerated bias aging tests
0.2 0.4 0.6 0.8 1.0
0
5
10
15
20
25 P3G1T7
Cu
rre
nt
Ga
in
Vbe [V]
Beta_0
Beta_1
Beta_2
Beta_4
Beta_8
Beta_16
Beta_24
Beta_72
Beta_250
Beta_500
Beta_750
Beta_1000
Beta_1250
Beta_1500
Beta_200040% At 0.95V
vc [E+0]
ic
.m
ic.m
@2
50
0h
[E
-3]
0.0 0.5 1.0 1.5 2.0 2.5 3.0-5
-0
5
10
15
20
25
0,2 0,4 0,6 0,8 1,010
-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
I (
A)
P3/G1/T7
VBE
(V)
0 to 72 hrs
250 to 2000 hrs
2500 hrs
IC
IB
15/27
Modeling through TCAD
TCAD simulations:
Introduction of donor traps on the entire surface of the emitter-base junction (trap level at ET-EV=0.83eV) IC, IB degradation (0.6V≤VBE≤1V).
0 1000 2000 30000,0
5,0x1011
1,0x1012
1,5x1012
E-B
junction d
onor
trap d
ensity @
Et-
Ev=
0,8
3eV
Time (hr)
Bias P4
Bias P3
Bias P2
Bias P2'
Linear fit
AE=0,7x7µm
2
Location Type Energy (ET-EV)
Emitter Sidewall Donor 1.3 eV
Extrinsic Base Acceptor 0.4 eV
Before aging the trap parameters and their locations
Recombination tunneling current at EB junction (0.2V≤VBE≤0.6V)
0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,910
-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
Meas @ 0h
TCAD (no EB traps)
Meas @ 1250h
TCAD (NT=1,15x10
-12cm
-2)
Curr
ents
(A
)
VBE
(V)
AE = 0,7x7µm
2
Jc = 400kA/cm
2
Tj = 125°C
16/27
Electrical modeling through HiCuM
The internal base current injected across the B-E junction is given by:
' '
exp 1 exp 1BEiS REiS
BEi REi
B E B EjBEi
T T
v vi
VI
m VI
m
The base current injected across the emitter periphery is given by:
* *exp 1 exp 1BEpS REpS
BEp RE
B E B EjBEp
T Tp
v vi
VI
m VI
m
Hicum L2
Parameter
Initial value 2500 hr aging
(P3)
Ibeis 0 34.0 E-15
Mbei 1.340 1.340
Ireis 598.9 E-15 598.9 E-15
Mrei 1.699 1.699
Ibeps 178.3 E-15 178.3 E-15
Mbep 1.517 1.517
Ireps 0 1.2 e-9
Mrep 4 4
IS 2.338 E-15 3.195 E-15
RE 4.01 4.86
17/27
HiCUM Parameter evolutions due to stress
0 500 1000 1500 2000 25000
5
10
15
20
25
30
35 P4
P3
P2
P2'
Linear fit
Ibe
is (
fA)
Stress time (hr)
0 500 1000 1500 2000 25002,2
2,4
2,6
2,8
3,0
3,2
3,4 P4
P3
P2
P2'
Linear fit
IS (
fA)
Stress time (hr)
0 250 500 750 1000 1250 15000,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
2,0
Ire
ps (
nA
)
time (hr)
P2
P2'
P3
P4
Exponential fit
of Ireps
1
1,05
1,1
1,15
1,2
1,25
0 500 1000 1500 2000 2500 3000re
/re
0
stress time (hr)
P4
P3
P2
P2p
Linéaire (P4)
Linéaire (P3)
Linéaire (P2)
Linéaire (P2p)
18/27
Electrical aging model
tTk
EJt
B
xax
CJT
,,
x,x expBAI
2,50 2,55 2,60 2,65 2,7010
-3
10-2
10-1
Ea, Ibeis
= 0.776 eV
constant increase
rate of Ibeis
of IS
fitted line
1000/T (1/K)A
T,J(I
be
is)
Ea, IS
= 1.32 eV
10-6
10-5
10-4
10-3
AT
,J (IS)
0 500 1000 1500 2000 2500 3000
0
10
20
30
40
50
60
Ibe
is (
fA)
Stress time (hr)
P4
P3
P2
P2p
P4
P3
P2
P2'
a, Ibeis = 0.776 eV
Where IX denotes IBEiS and IS parameters
Both junction temperature and current density dependence
Arrhenius Plot (T dependency)
Fitted lines following above equation
19/27
Implementation into HiCuM
Three new nodes that give IX(t, T,JC) and RE(t, T,JC)
JTX
dt
dI,A
Tk
EJ
B
xax
CJT
,,
x, expBA
module hic2_full (c,b,e,s,tnode,ibeis_out,is_out,re_out);
branch (ibeis_out) br_ibeisout;
branch (is_out) br_isout;
branch (re_out) br_reout;
// Aging model parameter initialization
parameter real ibeis0 = 0; is0 = 2.338e-15; re0 = 4.01; bibeis = 10.28e-15;
eibeis = 775.5m; alpha1 = 1.4; bis = 130.6p; eis = 1.206; alpha2 = 1.417;
aeff = 3.28E-8; (info="Effective emitter area unit cm2") ; atsf = 1.0; flage = 1
(info="Flag for turning on and off aging effect") ; bre = 2.778m;
ere = 543m; alpha3 = 771.4m;
// Declaration of variable
real aibeis,ais,are,ibeis,is,re;
//Model initialization
ibeis = V(br_ibeisout)+ibeis0; is = V(br_isout)+is0;
re = V(br_reout)*re0;
//Model evaluation
aibeis = bibeis*exp(-ibeis/((`P_K/`P_Q)*Tdev))*pow(((itf/1000.0)/aeff),alpha1);
ais = bis*exp(-eis/((`P_K/`P_Q)*Tdev))*pow(((itf/1000.0)/aeff),alpha2);
are = bre*exp(-ere/((`P_K/`P_Q)*Tdev))*pow(((itf/1000.0)/aeff),alpha3);
// Load Source
if (flage !=0) begin : Bias_aging
if (analysis("tran")) begin
if (analysis("ic")) begin
V(br_ibeisout) <+ 0.0;
V(br_isout) <+ 0.0;
V(br_reout) <+ 1.0;
end else begin
I(br_ibeisout) <+ -atsf*aibeis;
I(br_ibeisout) <+ ddt(V(br_ibeisout));
I(br_isout) <+ -atsf*ais;
I(br_isout) <+ ddt(V(br_isout));
I(br_reout) <+ -atsf*are;
I(br_reout) <+ ddt(V(br_reout));
end
end else begin
V(br_ibeisout) <+ 0.0;
V(br_isout) <+ 0.0;
V(br_reout) <+ 1.0;
end
end else begin
V(br_ibeisout) <+ 0.0;
V(br_isout) <+ 0.0;
V(br_reout) <+ 1.0;
end
20/27
Simulation results: Real aging conditions
Current Voltage regulation loop to maintain P3 bias condition (JC=400 kA/cm2 or IC= 13.33 mA and
VCE = 2.5V
+
-
VCE2.5V
Iset13.33mA
+
-
+
-
VcVs
IcIs
C
1uF
Q1NPN
R11
Experimental set up Simulation set up in ICCAP Software
21/27
Simulation results: Real aging conditions
P3 bias condition (JC=400 kA/cm2 or IC= 13.33 mA and VCE = 2.5V
time [E+6]
ib
[E
-3]
0 2 4 6 80.5
0.6
0.7
0.8
0.9
1.0
1.1
time [E+6]
vb [E
-3]
0 2 4 6 8838
840
842
844
846
848
850
22/27
Simulation results: circuit level
Common emitter amplifier
DC operating point (near peak fT condition):
Vbb=2V(DC)
AC amp=1V
Frequency=1GHz
Rb=1.0KΩ
Rc=120Ω
Vcc=2V
Thermal node
Ibeis-out
b
c
e
s
IS_out
Re_out
23/27
Transient Simulation results: circuit level
150 years (Aging time) 150 years (Aging time)
150 years (Aging time) 150 years (Aging time)
simulation time [s] [E-9]
IC
[A]
[E-3
]
0 200 400 600 800 10002
4
6
8
10
12
14
simulation time [s] [E-9]
VC
[V]
[E+0
]
0 200 400 600 800 10000.0
0.5
1.0
1.5
2.0
simulation time [s] [E-9]
tem
p [d
egre
e C
] [E
+0]
0 200 400 600 800 10008
9
10
11
12
13
simulation time [s] [E-9]
ibei
sout
[A
] [
E-1
5]
0 200 400 600 800 10000
2
4
6
8
10
12
24/27
Time scales
Three different time scales:
Electrical operating conditions (e.g.: frequency f=1GHz or higher, period t=1ns or less)
Thermal effect (CTH*RTH thermal time constant: 8 ns to 10ns)
Aging effect has to be simulated with respect to life time of the system (several years)
• Introduction of ATSF: Aging Time Scale Factor
• Gives a parallel time scale: actual time scale * ATSF (5x1015)
• CTH=3 pJ/K, Thermal time constant = 8 ns
25/27
Discussion
Implementation of “aging” into HiCuM
Adapt time scales: ATSF and CTH
Convergence
No particular problems detected so far
Allowed parameter ranges have to be checked
26/27
Conclusion
Investigation of reliability on InP HBTs
Measurements and compact modeling at t=0
Aging of devices at different current and bias stress conditions (up to 2500h) + intermediate characterization + parameter extraction
Physical modeling of aging and extraction of aging law
Electrical modeling of aging
Link between physical and electrical modeling results
Development of new compact model including aging
Application to circuit design (future work 100G modulator driver circuit)
27/27
This work is a part of the ROBUST project supported by the French Government through the ANR
Program “VERSO: Réseaux du futur et services”.
Thanks to III-V Lab (Alcatel -Lucent) for fruitful discussions and wafer supply.
Robust Website: http://extranet.ims-bordeaux.fr/ROBUST/
Acknowledgement
28/27
Additional slides (1/3)
0.4 0.6 0.8 1.010
-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
Cu
rre
nt
(A)
VBE (V)
Measurement
TCAD
0.2 0.3 0.4 0.5-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5 V
BE = 1,1V
VBE
= 1,0V
VBE
= 0,9V
VBE
= 0,8V
VBE
= 0,7V
VBE
= 0,6V
VBE
= 0,5V
BufferEmitter Collector
BV
energ
y level (e
V)
distance (µm)
BC
Base
blocking
spike
29/27
Additional slides (2/3): Physics of InP HBT: Transport across E-B junction
Thermionic Emission VS Thermionic Field Emission
Conventional transport cease to be valid at heterojunction interface
Currents and energy flux are then define by interface conditions
Thermionic Emission: Allow to take into account thermionic transport above the E-B junction discontinuity
Thermionic Field Emission: allow to take into account the field dependent tunneling and thermionic electron transport respectively through (through tunnel effect) and above the E-B junction discontinuity
ΔEC = 0.25eV TFE occurs
Determination of the tunnel mass
0,20 0,25 0,30 0,35 0,40 0,45 0,500,0
0,2
0,4
0,6
0,8
1,0
1,2
En
erg
y L
ev
el
(eV
)
Distance (µm)
Thermionic
Emission (TE)
Thermionic Field
Emission (TFE)
0,20 0,25 0,30 0,35 0,40 0,45 0,500,0
0,2
0,4
0,6
0,8
1,0
1,2
En
erg
y L
ev
el
(eV
)
Distance (µm)
Thermionic
Emission (TE)
Thermionic Field
Emission (TFE)
0,5 0,6 0,7 0,8 0,9 1,010
-6
10-5
10-4
10-3
10-2
10-1
100
Co
lle
cto
r c
urr
en
t (A
)
VBE
(V)
Measurement
mt=0,5 (TCAD)
mt=0,2 (TCAD)
mt=0,1 (TCAD)
mt=0,05 (TCAD)
mt=0,02 (TCAD)
mt=0,01 (TCAD)
T10B3H7
30/27
Additional slides (3/3)
ic [LOG]
ft.m
ft.s
[E
+9
]
1E-4 1E-3 1E-2 1E-10
100
200
300
400
-VBC [E+0]
C
jc.m
C
jc.s
[E
-15
]
-3 -2 -1 0 10
50
100
150