Trapping Investigation of the GaN HEMT Devices Using the ...
GaN Low Noise Broadband Amplifiers and Technology · Why GaN LNA? •NF similar to GaAs HEMT...
Transcript of GaN Low Noise Broadband Amplifiers and Technology · Why GaN LNA? •NF similar to GaAs HEMT...
GaN Low Noise Broadband Amplifiers and Technology
WFE: Gallium Nitride for Low Noise Amplifier Applications
Kevin W. Kobayashi, RFMD
Mike Wojtowicz, Northrop Grumman
Outline
• Low Noise GaN HEMT Technology
• Device Design
• NF characteristics- NG
• Survivability
• Trends in Literature
• Broadband S-/C-band LNA Design
• Wide-band Linear Applications
• Design Topology Trades
• Linear Cascode LNA example
• Technology Comparison of LNA NF-IP3
• CATV Example
• Future Trends in GaN LNAs
Materials Outline
• Why GaN?
• Intrinsic noise sources in GaN HEMTs
• Back barrier design
• Bias impact to NFmin
• Gate size impact to NFmin
• Material profile impact to NFmin
• Summary
Why GaN LNA?
• NF similar to GaAs HEMT
• 10-15 dB increase in power
surge survivability
• No need for protection
circuit
• Simplifies transceiver
design
• Improves spurious-free
dynamic range (SFDR)
GaN
GaAs
InP
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 10 20 30 40 50 60
Vds (V)
Pu
lsed
Id
s (
A/m
m) GaN HEMT Pulsed IV GaNGaN
GaAsGaAs
InP
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 10 20 30 40 50 60
Vds (V)
Pu
lsed
Id
s (
A/m
m) GaN HEMT Pulsed IV
GaN HEMT simplifies receiver front-end electronics
Survivability
• GaN LNAs provide >30 dBm overdrive survivability
Frequency
(GHz)
Gain
(dB)
Noise Figure
(dB)
Survivability
(dBm)
Reference
3.5 – 7.0 20 2.3 33.0 [4-1]
10 12 0.8 31.6 [4-2]
1 - 8 16 2.0 38.0 [4-3]
4.5 - 16 10 2.5 37.3 [4-4]
0.6 – 5.0 10.1 3.0 30.0 [4-5]
2 - 12 9 3.0 36.0 [4-6]
4 – 6.5 10 1.9 31.0 [4-7]
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0 10 20 30 40 50 60 70
Nfm
in (d
B)
Frequency (GHz)
GaN HEMT
GaAs pHEMT
InP pHEMT
Noise Comparison
• GaN provides equivalent noise to 0.1um GaAs pHEMT
[5-1]
[5-1]
[5-2]
[5-3] [5-1]
[5-4]
[5-5] [5-6]
Noise Sources
• Four primary intrinsic sources of noise in
AlGaN/GaN HEMTs [6-1], [6-2]
• Velocity fluctuation of channel electrons due
to scattering
• Heterojunction interface
• Lattice (phonon)
• Impurities
• Frequency independent
• Vg fluctuations
• Highly correlated to Id fluctuations in channel
• Frequency independent
• Gate leakage due to injection of electrons into
the channel
• Random process
• Results in shot noise
• Electron trapping
• Surface states
• Interface states
• Bulk defects
• 1/f
Back-barrier
GaN Channel
AlGaN Schottky
Gate Source Drain
SiN
SiC
Le
aka
ge
- Traps
- Velocity
Fluctuation
AlN Insert
Vg
Back Barrier Profiles
AlxGa1-xN Schottky Barrier
GaN Buffer
AlxGa1-xN Schottky Barrier
GaN Channel
AlxGa1-xN buffer
GaN Buffer
AlGaN Back-barrier
• Double heterostructure profiles
provide enhanced carrier
confinement
• Mitigate velocity fluctuations
-4
-3
-2
-1
0
1
2
0 200 400 600 800
En
ergy (eV
)
Thickness (Ang.)
Conduction Band
Valence Band
GaN buffer
AlGaN back-barrier
1-D Poisson Simulations
Double Heterostructures
• Double Heterostructures reduce short channel effects for Lg < 0.25um
• Improves pinch-off
• Reduces sub-threshold leakage
• Good pinch-off necessary for low noise performance
GaN Back-Barrier
GaN Back-Barrier
AlGaN Back-Barrier
10-5
10-3
10-1
101
103
Noise vs Bias
• NFmin decreases with Id and increases slowly with Vd
• Dominated by channel velocity fluctuations
• Able to maintain low NFmin over wide drain bias condition
• Minimum NFmin at 100mA/mm (75% Idsp) and 2.5 – 5.0V
10 GHz NFmin/Ga Contours
0.2um Lg, 4f200um device
AlGaN back-barrier
0.1um InP pHEMT optimal bias
0.5 – 1 V Vds, 100mA/mm
0.1um GaAs pHEMT optimal bias
2V Vds, 100mA/mm
0.2um GaN pHEMT optimal bias
4V Vds, 100mA/mm
0.4
Noise vs Gate Length
• NFmin is constant against gate size for a constant gain and gate
leakage
• Smaller gate lengths improve NFmin at higher frequencies
0.2um Lg w/ AlN 0.2um Lg w/ AlN
0.1um Lg w/ AlN 0.1um Lg w/ AlN
5V-100mA/mm, 4f200um device
AlN Insert, AlGaN back-barrier
NFmin = 1 + K 2 p f Cgs
√ gm √ Rg + Rs
Noise vs. Gate Leakage
• NFmin is expected to increase rapidly with Ig (~0.5dB for 10x
increase in Ig) [10-1]
0.2um Lg
0.25um Lg
0.2um Lg
0.25um Lg
0.25um: Ig ~1x10-3 mA/mm
0.2um: Ig ~1x10-4 mA/mm
~ 10X difference in Ig
5V-150mA/mm, 4f200um device
AlGaN back-barrier
10-4
10-3
10-2
10-1
100
10-5
Noise vs AlN Insert
• AlN insert layers reduce Rsh
• Does not impact NFmin at best noise bias [12-1]
0.2um Lg w/o AlN
0.2um Lg w/ AlN 0.2um Lg w/ AlN
0.2um Lg w/o AlN
Imax Rsh
0.2um w/o AlN 0.96 A/mm 471
0.2um w/ AlN 1.1 A/mm 366
5V-100mA/mm, 4f200um device
AlGaN back-barrier
Noise vs Back-Barrier
• NFmin degrades with poor channel confinement
10GHz NFmin Contour
0.25um Lg, GaN Back-Barrier 10GHz NFmin Contour
0.25um Lg, AlGaN Back-Barrier
GaN Back-barrier
AlGaN Back-Barrier
10-5
10-3
10-1
101
103
Materials Summary
• GaN HEMTs provide similar NFmin to GaAs HEMTs and
provide >30dBm survivability
• Eliminates need for protection diodes resulting in overall
system noise reduction
• Key noise sources consistent with other HEMT devices
• Primary contributor to NFmin is gate leakage and poor
channel confinement
GaN LNA Motivation
•GaN LNA Motivations • Survivability
• Combination of Low NF- High Linearity
• Wide BW (decade/octave)
•Enables Future Applications • Software defined Radios
• Higher Spectral Efficient P2P
• RF on Fiber
• Extended CATV
Bandwidth
Sensitivity
(Low NF)
Linearity
Power/Efficiency
SDR Radios
Network Reach
> Decade BW
CATV
Multi-carrier
Multi-mode/format
GaN Front-End Multi-Octave BW Infrastructure Systems
0
0.5
1
1.5
2
2.5
3
3.5
4
0 2 4 6 8
Nois
e F
igure
(dB
)
Frequency (GHz)
State-of-the-Art GaN MMIC Noise Figure
[6] SIRENZA-NG
[3] NG
[4] NG
[1] HRL
[2] UCSB
[5]NG [9] NG
2011 CSIC [14]
Cascode LNA
8-Watt
[11]
[10]
[7] RFMD-NG, T= -10C
CS-LNA
2-Watt
< 1 Watt
Dual-gate
FB LNA
Broadband Linear-Low Noise Topology Considerations
Common-Source
Best NF
Ls-optimum Gopt-S11
Gain slope
WHY?
Darlington FB
Widest IP3-BW
Decade Gain-BW
Limited NF
WHY?
Distributed Amp
Widest Gain-BW
High Power-BW
Limited LF NF
WHY?
Cascode FB
Wide Flat Gain-BW
Good NF
Good IP3/IP2
Poor PAE
2007 RFIC
2011 CSIC
2008 CSIC
Noise contribution due to
unity gain of transistor M1.
Soln. Pre-Amp.
Noise contribution due to
Input termination resistor in
shunt with input. Soln. Active load? 2009 RFIC
Gain roll-off due to source
Inductance degeneration.
Soln. Use gate inductance.
Common-gate increase I-V
knee voltage and reduces
dynamic voltage swing.
OUT
IN
LchokeVdd = 15V
Cbypass
Idd
0.2um x 50um
x 24
Rfb
Rg
Ls
Cfb
Vgs
OUT
IN
Rfb
Rg
Vg1
MC M1
M2
MC
Rdc
Rfb
Cfb
Rs
Cbyp
Rout
Rin
Cout
Cin
TLin1
Cg2 Cg2 Cg2 Cg2
Vg1
Vg2
OUT
IN
Cg2_ext
Cin_ext
Cout_ext
M1_cs M2_csM8_cs
M9_cs
M1_cg M2_cg M8_cg M9_cg
TLin2 TLin8 TLin9 TLin
TLout1 TLout2 TLout8 TLout9 TLout
. . .
. . .
. . .
Common-Source vs. Cascode
Performance
Common-
source
Cascode/*Dual
gate
Practical Vdd 20V (T-gate) 40V
Pout , IP3 4-6 dB improvement
Idd 250mA/mm same
Tj @ 85C
base
~200C ~*200C
NF higher (id1_n,id2_n)
BW much wider
Gain much higher, flatter
Stability poorer
Cascode Characteristics
10 20 30 40 50 60 70 80 90 0 100
10
20
30
40
0
50
Frequency (GHz)
CASCODE
COMMON-SOURCE
Ma
x G
ain
(d
B)
Wg = 500um HEMT
Maximum Available Gain I-V characteristics
10 20 30 40 50 60 70 0 80
0.2
0.4
0.6
0.8
1.0
0.0
1.2
VDS
COMMON-SOURCE CASCODE
A/mm
IDS
(A
/mm
)
Cascode has higher MAG Cascode has higher Ro, good IP3
But higher Vknee, poorer PAE
*Tj~200C @ 20V-250mA/mm
Device Noise Characteristics
freq (500.0MHz to 3.000GHz)N
PA
R_
Wg
_6
00
um
_2
50
mA
pe
rmm
..S
op
tN
PA
R_
Wg
_1
mm
_2
50
mA
pe
rmm
..S
op
tN
PA
R_
Wg
_2
mm
_2
50
mA
pe
rmm
..S
op
tN
PA
R_
Wg
_3
mm
_2
50
mA
pe
rmm
..S
op
t
Gopt
Wg = 3 mm
2 mm
1 mm
0.6 mm
NFmin ~ 0.65 dB @ 2 GHz
0.0
0.5
1.0
1.5
0 2 4 6 8 10
NF
min
(dB
)
Frequency (GHz)
4F200um Vds = 15V
50 mA/mm
100 mA/mm
150 mA/mm
250 mA/mm
300 mA/mm
IP3-Noise-match trade
•Wg =3mm IP3 > 50dBm
•Wg ~1mm better 50-ohm noise match
GaN Cascode Feedback Design Optimized for IP3-BW
Chip size is 1.6x1.3 mm2 GaN Cascode Feedback LNA
• Cascode
• Wg_total = 3 mm
• Vdd = 40V
• Idd = 500-750mA
4 finger x 125um
(Wg=500um unit cell)
Cascode Gain & NF Performance
-40
-30
-20
-10
0
10
20
30
0 1 2 3
Ga
in &
Re
turn
-Lo
ss (d
B)
Frequency (GHz)
40V-750mA
S21
S11
S22
2.92.4 2.3
2.5 2.53.0 2.9
3.6
3.02.7 2.7
3.0 3.2
3.8 3.7
4.6
0
1
2
3
4
5
6
0 1 2 3 4
No
ise
Fig
ure
(d
B)
Frequency (GHz)
40V-750 mA
40V-500 mA
S-parameters
• Gain 20dB
• BW ~ 250MHz -3 GHz
• LF Gain limited to on-chip Cap
Noise Figure
• 2.3-3.0dB @ 40V-500mA
• 2.7-3.8dB @ 40V-750mA
• Not as Low as predicted! WHY?
Simple Noise Contribution Calculation
CALCULATED
0
1
2
3
4
5
6
0 1 2 3 4
Nois
e F
igure
(dB
)
Frequency (GHz)
0
1
2
3
4
5
6
0 1 2 3 4
Nois
e F
igure
(dB
)
Frequency (GHz)
MEASURED
Channel Thermal Noise
4KT G(1/gm)
FB Resistor
Rg+Ri+Rs
Fukui
Equation
MEASURED
Channel Thermal Noise
4KT G(1/gm)
FB Resistor
Rg+Ri+Rs
Fukui
Equation
CALCULATED
MEASURED
Cascode LNA Linearity
54.352.7 53.3 51.9 51.8 51.4 50.8 52.0
50.748.6
50.248.4
50.048.0 48.0 48.4
20
30
40
50
60
0 1 2 3 4
OIP
3 (d
Bm
)
Frequency (GHz)
40V-750 mA
40V-500 mA
GaN
D-PHEMT
HFET
HBT-WB [14]
[5]
[7]
[6]
[3]
[10]
[1]
[12-13]
HBT-NB
NB= Narrow band tuned
WB= Wide band tuned
[14]
[2012 RFIC]
E-PHEMT
IP3-NF Technology Comparison
25
30
35
40
45
50
55
0 1 2 3 4 5 6 7 8
OIP
3 (d
Bm
)
Noise Figure (dB)
Summary of S-band LNA & Gain Block Performance
D PHEMT
E PHEMT
GaAs HBT
HFET/MESFETGaN HEMT
GaN MMIC Topology Comparison
Summary of GaN MMIC FB LNA Performance (S-, C-band)
Reference Topology Noise
Figure (dB)
OIP3
(dBm)
P1dB
(dBm)
LFOM
(IP3/Pdc) D (IP3-P1dB)
[1] Matched-FB 2.4 37.8* 9.5:1
[3], [5] Dual-gate FB
1.5 43 30 13
1.03 32 < 25
dBm 2.0:1
[6], [7] Source-Match-
FB
0.75-0.9 44-46 32.9 6.64:1 11-13
0.25-0.45 42-44 32.8 4.2:1 11.2
[12] Darlington 4.3** 43.5 31 3.7 12.5
[11], [13] DA 3.3 29 22 7
4.3** 42-44 30-33 ~2:1 11-12
This Work
[14] Cascode FB
2.5 48.4 36.8 3.5:1 11.7
3 51.9 38.5 5.2:1 13.4
Lowest
NF
Best
Combo
NF-IP3
Best
BW
Poor
thermal
mitigation
Gain
Roll-off
High NF
LF NF
Poor
PAE
GaN Power Doubler Amplifier Typical NTSC CATV Spectrum
CATV upgrades extend the BW beyond 1 GHz adding digital
channels to support HDTV, VOD, & high speed internet
GaN Device CATV Linearity
Courtesy Rainer Hillermeier - RFMD
CATV linearity is related to device Cdg linearity with Vds.
Lower Al composition results in improved GaN CATV linearity.
GaN Device CATV Linearity
[2009 BCTM Conference, Jeff Shealy, et.al.]
GaN provides 3.5 dB higher linear Output Power vs. GaAs
CATV CIN Linearity: GaN vs. GaAs
Courtesy Rainer Hillermeier - RFMD
GaN LNA Future Trends
• Decade BW Performance, No Filter
• Reconfigurable – SDR
• E/D GaN
• Insulated gate (reduce gate shot noise)
• THz Operation
• Linearization
• Heterogeneous Integration w/ Silicon
Acknowledgement
• Northrop Grumman
–Richard To, Wen-Ben Luo, Ioulia Smorchkova, Benjamin
Heying,YaoChung Chen, Mike Wojtowicz, Aaron Oki,
Schaffer Grimm, Willie O. Simmons, Ed Rezek, and Frank
Kropschot
• RFMD
–Rainer Hillermeier, Tony Sellas, Curtis Kitani, Robert Dry,
Don Willis, Daniel Jin, Joe Johnson, Dave Aichele, Jeff
Shealy, Karthik Krishnamurthy, Ramakrishna Vetury, Dane
Henry, Conrad Young, Alastair Upton, Brad Nelson, Dave
Runton, Jay Martin, Norm Hilgendorf
Broadband GaN LNA MMIC
• [1]Grant A. Ellis, et.al., “Wideband AlGaN/GaN HEMT MMIC Low Noise Amplifier,” in IEEE MTT-S Digest, Fortworth, TX, June, 2004, pp. 153-156.
• [2]Hongtao Xu, et.al., “A C-Band High-Dynamic Range GaN HEMT Low-Noise Amplifier,” IEEE Microwave and Wireless Components Letters, vol. 14, no. 6,
pp. 262-264, June, 2004.
• [3]S. Cha, et.al., “Wideband AlGaN/GaN HEMT Low Noise Amplifier for Highly Survivable Receiver Electronics,” in IEEE MTT-S Digest, Fortworth, TX,
June, 2004, pp. 829-832.
• [4]S.E. Shih, et.al., “Broadband GaN Dual-Gate HEMT Low Noise Amplifier,” in IEEE CSIC Symp. Dig., Portland, Oregon, October, 2007.
• [5]Michael V. Aust, et.al., “Wideband Dual-Gate GaN HEMT Low Noise Amplifier for Front-End Receiver Electronics,” in IEEE CSIC Symp. Dig., San
Antonio, TX, Nov., 2006.
• [6]K.W. Kobayashi, et.al., “A 2 Watt, Sub-dB Noise Figure GaN MMIC LNA-PA Amplifier with Multi-octave Bandwidth from 0.2-8 GHz,” in IEEE MTT Digest,
Honolulu, Hawaii, June, 2007, pp. 619-622.
• [7]Kevin W. Kobayashi, et.al., “A Cool, Sub-0.2 dB Noise Figure GaN HEMT Power Amplifier with 2-Watt Output Power,” IEEE Journal of Solid-State
Circuits, October, 2009.
• [8] E.M. Suijker, et.al., “Robust AlGaN/GaN Low Noise Amplifier MMICs for C-, Ku- and Ka-band Space Applications,” IEEE CSIC Symp. Dig. ,Greensboro,
NC, 2009.
• [9] S.E. Shih, et.al., “Design and Analysis of Ultra Wideband GaN Dual-Gate HEMT Low Noise Amplifiers,” IEEE IMS Dig., Boston, MA, June, 2009.
• [10] James Milligan, “Commercial GaN Devices for Switching and Low Noise Applications,” IEEE IMS Workshop Notes, WFA, Anaheim, CA, May, 2010.
• [11] W. Ciccognani, et.al., “An Ultra-Broadband Robust LNA for Defence Applications in AlGaN/GaN Technology,” IEEE IMS Dig., Anaheim, CA, May, 2010.
• [12] Kevin W. Kobayashi, *YaoChung Chen, *Ioulia Smorchkova, *Roger Tsai, *Mike Wojtowicz, and *Aaron Oki, “1-Watt Conventional and Cascoded GaN-
SiC Darlington MMIC Amplifiers to 18 GHz,” IEEE RFIC Symp. ,Honolulu, Hawaii, 2007.
• [13] Kevin W. Kobayashi, *YaoChung Chen, *Ioulia Smorchkova, *Benjamin Heying, *Wen-Ben Luo, *William Sutton,*Mike Wojtowicz, and *Aaron Oki,
“Multi-Decade GaN HEMT Cascode-Distributed Power Amplifier with baseband Performance,” 2009 IEEE RFIC symp., Boston, MA, June 6th.
• [14] Kobayashi, Kevin W. ”An 8-Watt 250-3000 MHz Low Noise GaN MMIC Feedback Amplifier with > +50 dBm OIP3,” 2011 IEEE CSIC Symposium, Hawaii,
Oct. 16-19.
Bibliography
Bibliography
Survivability
• [4-1] M. Rudolph, R. Behtash, R. Doerner, K. Hirche, J. Würfl, W. Heinrich, and G. Tränkle, “Analysis of the Survivability of GaN Low-Noise Amplifiers,”
IEEE Trans. Microw. Theory Tech., vol. 55, no. 1, pp. 37 – 43, Jan. 2007.
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Electronics,” IEEE CSIC Symp. Dig., San Antonio, TX, Nov. 2006.
• [4-4] M. Micovic, A. Kurdoghlian, T. Lee, R. O. Hiramoto, P. Hashimoto, A. Schmitz, I. Milosavljevic, P. J. Willadsen, W.-S. Wong, M. Antcliffe, M.
Wetzel, M. Hu, M. J. Delaney, and D. H. Chow, “Robust Broadband (4 GHz – 16 GHz) GaN MMIC LNA,” 2007 IEEE Compound Semiconductor Integrated
Circuit Symposium.
• [4-5] S. Cha, Y.H. Chung, M. Wojtowicz, I. Smorchkova, B. R. Allen, J.M. Yang, and R. Kagiwada, “Wideband AlGaN/GaN HEMT Low Noise .Amplifier
For Highly Survivable Receiver Electronics,” IEEE MTT-S Digest, Fortworth, TX, June, 2004, pp. 829-832.
• [4-6] M. Micovic, A. Kurdoghlian, H. P. Moyer, P. Hashimoto, A. Schmitz, I. Milosavljevic, P. J. Willadsen, W.-S. Wong, J. Duvall, M. Hu, M. Wetzel , and
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Microwave and Wireless Components Letters, vol. 14, no. 6, pp. 262-264, June, 2004.
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Material/Device Noise
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pseudomorphicHEMTs,” IEEE Trans. Electron Devices, vol. 44, pp. 1367–1374, Sep.1997.
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vol.17, no. 10, pp. 482–484, Oct. 1996.
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ElectronDevices Meeting Tech. Dig., Dec. 11–14, 1994, pp. 907–910.
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Theory Tech., vol. 51, no. 5, May 2003.
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Performance,” IEEE Electron Device Lett., vol. 24, no. 9, pp. 535-537, Sep. 2003.
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AlGaN/GaN HEMTs,” IEEE Electron Device Lett., vol. 27, no. 1, Jan. 2006
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of AlGaN/GaN HEMTs,” IEEE Trans. Microw. Theory Tech., vol. 53, no. 2, pp.762 – 768, Feb. 2005.
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Int. Symp. On RF Integr. Tech., pp. 276 – 279.
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