MWP 2003 Jin-Wei Shi Si/SiGe Heterojunction Phototransistor Jin-Wei Shi 1,*, Z. Pei 1, Y.-M. Hsu 1,...
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Transcript of MWP 2003 Jin-Wei Shi Si/SiGe Heterojunction Phototransistor Jin-Wei Shi 1,*, Z. Pei 1, Y.-M. Hsu 1,...
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Si/SiGe Heterojunction Phototransistor
Jin-Wei Shi1,*, Z. Pei1,
Y.-M. Hsu1, F. Yuan2, C.-S. Liang1, Y.-T. Tseng1, P.-S. Cheng1, C.-W. Liu1,2, S.-C. Lu1, M.-J. Tsai1
1 Electronics Research and Service Organization (ERSO), Industrial Technology Research Institute (ITRI), Hsinchu, 31040, TAIWAN
2 Department of Electrical Engineering, National Taiwan University, Taipei 10617, TAIWAN.
*Current address: Department of Electrical Engineering, National Central University, Taoyuan, 320, TAIWAN.
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
• Motivation• Structures of Si/SiGe Heterojunction Phototra
nsistor• Electrical measurement results • Optical dc measurement results • Side-Wall Terminal Technique & Optical Tran
sient Measurement Results at 850nm • Conclusion
Outline
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Outline
• Motivation• Structures of Si/SiGe Heterojunction Phototra
nsistor• Electrical measurement results • Optical dc measurement results • Side-Wall Terminal Technique & Optical Tran
sient Measurement Results at 850nm • Conclusion
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
• Extremely High Responsivity• Over ~10A/W• Much lower operation voltage than Avalanche Photodiode (APD)• Much lower cost than APD and semiconductor optical amplifier (SOA)
• Circuit Level Integration• HBT+HPT (Hetero-junction Photo-transistor) OEIC1 !!
• Lower fabrication cost than p-i-n+HBT OEIC • Analog fiber communication application of HPT2
• Clock recover O-E circuit, O-E Mixer
• Speed is critical issue for the application of HPT!!• Optical fT for analog fiber application1
• Electrical f3dB for digital fiber application • We will demonstrate a novel method to improve the gain-bandwidth pr
oduct of HPT in this presentation !!
Photo-transistor for Fiber Communication Application
1. H. Wang, et al., IEEE Trans. Microwave Theory Tech., vol. 34, Dec. 1986.
2. H. Kamitsuna, et al., IEEE Trans. Microwave Theory Tech., vol. 49, Oct. 2001.
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Why Si/SiGe Based HPT ?
• Low Responsivity of Si based p-i-n Photodetectors (PDs)1 • High operation gain of photo-transistor can overcome this drawback• Much Lower Operation Voltage than APD
– Without voltage or temperature control circuit– Low cost !!
• High gain/speed2, yield and reliability of SiGe HBT– In plane structure of Si/SiGe based HBT has higher yield and reliability t
han etch-mesa structure of III-V based HBT3
• Si/SiGe based TIA+HPT– Almost without modification of standard TIA fabrication process
– Low cost!! • Analog nonlinear application of SiGe based HPT
– Clock recover O-E circuit, O-E Mixer
1. B. Yang, et al., IEEE Photonic Technology Letters, vol. 15, May 2003.
2. B. Jagannathan, et al., IEEE Electron Device Letters, vol. 23, May, 2002.
3. Z. Ma, et al., IEEE Trans. Microwave Theory Tech., vol. 50, April, 2002.
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Outline
• Motivation• Structures of Si/SiGe Heterojunction Phototra
nsistor• Electrical measurement results • Optical dc measurement results • Side-Wall Terminal Technique & Optical Tran
sient Measurement Results at 850nm • Conclusion
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei ShiCross-Sectional and Top Views of Fabricate
d Si/SiGe HPT
Two types of HPT are fabricated (with/without MQW)
The photo-absorption process is enhanced by incorporating Si/SiGe MQW at B-C junction!!
Fiber communication long wavelengths (1.3~1.55m) photo-absorption can be achieved by using SiGe alloy1
MQW at B-C Junction !! The same as SiGe HBT !!
1. H. Lafontaine, et al., Journal of applied physics vol. 86, Aug. 1999.
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Outline
• Motivation• Structures of Si/SiGe Heterojunction Phototra
nsistor• Electrical measurement results • Optical dc measurement results • Side-Wall Terminal Technique & Optical Tran
sient Measurement Results at 850nm • Conclusion
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
QW structure at B-C junction doesn't’t affect the electrical gain
significantly !!
Gummel Plot of Si/SiGe HPT with/without MQW
0.4 0.6 0.8 1.01E-11
1E-9
1E-7
1E-5
1E-3
0.1
=~200
I c,I b(
A)
Vbe
(V)
Ib MQW
Ib HBT
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
fT fmax of Si/SiGe HPT with/without MQW
ft is the key parameter at the application of analog circuit
QW structure has higher fmax but lower ft than ordinary HBT due to the extra thickness of MQW at collector !!
High conversion gain of SiGe based O/E mixer1 can be expected due to high ft and high
1. H. Kamitsuna, et al., IEEE Trans. Microwave Theory Tech., vol. 49, Oct. 2001.
10k 100k
10
20
30
40
50
Peak fmax
Peak ft
f T,f m
ax (
GH
z)
Jc(A/cm2)
MQW ft MQW fmax HBT ft HBT fmax
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Outline
• Motivation• Structures of Si/SiGe Heterojunction Phototra
nsistor• Electrical measurement results • Optical dc measurement results • Side-Wall Terminal Technique & Optical Tran
sient Measurement Results at 850nm • Conclusion
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
QW structure at B-C junction enhance the responsivity significantly!!
The responsivity is much higher than the reported values (~0.1A/W) of Si based PDs at 850nm wavelength1
Higher responsivity can be expected by improving coupling optics!!
Excitation Wavelength: 850nm
1. B. Yang, et al., IEEE Photonic Technology Letters, vol. 15, May 2003.
Photo-DC Measurement Results-with/without QW structure
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
0 1 21E-5
1E-4
Breakdown (~2.5V)!!Responivity Enhancement !!
EDCBA
Trace A~E: Optical Power 0.2mW~0.4mW (Step:0.05mW)
Pho
tocu
rren
t (A
)
VCE
(V)
0.20 0.25 0.30 0.35 0.40
30
60
90
120
150
180 Photon-absorption Bleach
D
A,B,C
A:VCE
=0.5VB:V
CE=1V
C:VCE
=2VD:V
CE=2.5V
Pho
to-c
urre
nt (A
)
Optical Power (mW)
Responsivity enhancement1 & Photo-absorption bleach2 at near breakdown voltage !! Optoelectronic Mixer1,2
1. E. Suematsu and N. Imai, IEEE Trans. Microwave Theory Tech., vol. 44, pp.133-143, 1996. 2. M. Tsuchiya, and T. Hosida, IEEE Trans. Microwave Theory Tech., vol. 47, 199
9.
Photo-DC Measurement Results- Nonlinear Behaviors at Near Breakdown Region
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Outline
• Motivation• Structures of Si/SiGe Heterojunction Phototra
nsistor• Electrical measurement results • Optical dc measurement results • Side-Wall Terminal Technique & Optical Tran
sient Measurement Results at 850nm • Conclusion
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
• Speed limits the application of HPT in the field of digital fiber communication – Poorer speed performance than p-i-n or APD– What are the prior arts to improve speed performance of
HPT ?
• Base termination technique1,2,3
– Turn on the B-E junction to remove the excess hole at base– Significant speed enhancement 1,2
– Huge dc power consumption (dark current)!!– At the expense of optical gain1,2!!– What is the optimum solution?
Speed Performance of HPT
1. M. Y. Frankel, et. al., IEEE Journal of Quantum Electronics, vol. 31, Feb. 1995.2. T. F. Carruthers, et. al., Appl. Phys. Lett., vol. 63, no. 14, Oct. 1993. 3. S. Chandrasekhar, et. al., IEEE Electron Device Letters, vol. 12, Oct. 1991.
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
• General solutions for speed enhancement in III-V and Si based HPTs
• Especially suitable to SiGe based HPTs with planar structure
• Significant speed improvement with less gain sacrifice and increase in dark current
• Open a new field for HPTs OEIC (Opto-Electronic Integrated Circuit)
Our Novel Solution-Side-Wall Terminal Technique
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Photo-generated hole can be removed by side-wall terminal (lateral p-n junction) instead B-E junction
Similar to standard substrate contact process of SiGe based HBT!!
Cross-Section of Novel Side-Wall Contact Si
Ge Based HPTs without MQW
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
“Hole trapping problem” due to thick MQW/MQD barrier can be eliminated by P-type doped at well region and side-wall terminal
Cross-Section of Novel Side-Wall Contact
MQW/MQD SiGe Based HPTs
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei ShiUsing Substrate Contact to Primarily
Demonstrate this Idea
Standard SiGe HPT substrate contact process!!
Substrate contact is grounded with emitter contact
Large parasitic resistance !!
Better speed performance can be expected!!
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
FWHM enhancement : 2.5 ns 0.85 ns
Photocurrent reduction : 15 A 8.7A
Superior Performance of HPT without MQW by using Side-Wall Terminal Technique
FWHM enhancement : 2.5 ns 0.95 ns
Photocurrent reduction : 15 A 0.1 A
Base terminal floating :
Trace A : Side-wall terminal floating
Trace B : Side-wall terminal grounding
Side-wall terminal floating :
Trace A : Base terminal floating
Trace B : Base terminal grounding
0 100 200 300 400 500-0.2
0.0
0.2
0.4
0.6
0.8
1.0 VCE
= 1 VAvg. Optical Power: 5W
B
A
Am
plitu
de (
a.u.
)
Time (ns)0 100 200 300 400 500
-0.2
0.0
0.2
0.4
0.6
0.8
1.0 VCE
= 1 VAvg. Optical Power: 5W
B
A
Am
lpitu
de (
a.u.
)
Time (ns)
*Side-Wall contact terminal technique can achieve much higher gain-bandwidth product as compared with Base
terminal technique!!
Use Substrate contact to demonstrate this idea!!
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
*Side-Wall contact terminal is more useful than base terminal at quantized structure !!
0 100 200 300 400 500 600
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2 VCE
= 1 VAvg. Optical Power: 5W
Am
plitu
de (
a.u.
)Time (ns)
0 100 200 300 400 500 600-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2 VCE
= 1 VAvg. Optical Power: 5W
B
A
Am
plitu
de (
a.u.
)
Time (ns)
FWHM enhancement : 7.7 ns 1 ns
Photocurrent reduction : 90 A 45 A
FWHM enhancement : similar to 7.7 ns
Photocurrent reduction : 90 A 0.11 A
Base terminal floating :
Trace A : Side-wall terminal floating
Trace B : Side-wall terminal grounding
Side-wall terminal floating :
Trace A : Base terminal floating
Trace B : Base terminal grounding
Superior Performance of MQW HPT by using Side-Wall Terminal Technique
Use Substrate contact to demonstrate this idea!!
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
• Side-wall terminal can remove the storage hole at base region without huge dark current
• With less sacrifice for operated gain• Side-wall terminal can solve the problem of hole trapp
ing at MQW structure• SiGe based QW structure play important role for long wavelength d
etection
• The problem of hole trapping limits the speed performance of SiGe based PDs1
• Lateral conduction can solve this problem
• Open a new field for HPT based OEIC!!• Use substrate terminal to distort input RF signal
• Novel optoelectronic mixer1. C. Li et al., IEEE Photon. Technol. Lett., vol. 12, pp. 1373-1375, Oct. 2000.
Advantages of Side-Wall Terminal
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
0 400 800 1200-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Avg. Optical Power: 90nW
FWHM = 93 ps Bandwidth=~3GHz Instrument Limited Bandwidth
Am
pliti
ud
e (a
.u.)
Time (ps)
High Speed Performances by Using Side-Wall Termination
Technique under low power illumination
0 1000 2000 3000-0.2
0.0
0.2
0.4
0.6
0.8
1.0 Avg. Optical Power: 90nW
FWHM = 136 ps Bandwidth=0.5GHz
Am
pliti
ude
(a.u
.)
Time (ps)
HPT without MQW HPT with MQW
MQW structure has much higher optical gain than control SiGe HPT, but poorer speed performance !!
Speed performance of PDs can be improved significantly under low power excitation1
1. Y.-L. Huang and C.-K. Sun, Journal of Lightwave Technology, vol. 18, 2000.
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
0.8 1.2 1.6 2.0 2.40
15
30
45
60
75
90
HPT without MWQ (3GHz) HPT with MQW (0.5GHz)
Bna
dwid
th-R
esp
onsi
vity
P
rodu
ct (
GH
z-A
/W)
VCE
(V)
Bandwidth-Responsivity Products of Different Types of HPT
High speed (~3GHz) with reasonable responsivity (>0.4A/W) performances of standard HPT ensure its application of 850nm short-reach data comm. !!
High bandwidth-efficiency product and high ft performance of MQW HPT imply its applications in low-cost clock recovery circuits or optoelectronic mixer !!
MWQ structure has much higher bandwidth-responsivity product than ordinary HPT !!
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
Outline
• Motivation• Structures of Si/SiGe Heterojunction Phototra
nsistor• Electrical measurement results • Optical dc measurement results • Side-Wall Terminal Technique & Optical Tran
sient Measurement Results at 850nm • Conclusion
Industrial Technology Research InstituteElectronics Research & Service Organization
MWP 2003
Jin-Wei Shi
• Two types of SiGe based HPT are demonstrated • MQW structure at B-C junction can improve responsi
vity significantly • Side-wall terminal technique can improve the speed p
erformance of two HPT structures significantly with less gain reduction and eliminate huge dc power consumption
• Ordinary HPT structure has the application of 850nm short reach 2.5G/bits data communication
• MQW HPT structure has the application of 850nm optoelectronic mixer
Conclusion