Future devices for Information Technology

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Future devices for Information Technology
2003. 4. 4.
Songcheol Hong
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Contents Electronic Devices (processing
devices) High speed devices(digital, analog,
RF) High power devices Memory
devices Optical Devices QWLD, QDLD
Optical communication devices GaN based
Devices Display
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High speed devices Digital,
Analog(RF) DSP upto Microwave frequencies
IEEE MTT Vol. 50, N0. 3, 2002 p900
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Power dissipation/ MIPS
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Digital circuits expands to Analog domain
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Trends in Transmitter Architecture(Mobile)
High Speed DSP (7GHz)
DC-DC converter
Vector Modulator
DSP
SDR One Chip Radio
Supply voltage control
Bias control
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Smart PA
Heterodyne type Base/gate bias voltage
control GaAs based PA
Gate/base bias control
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Dynamic supply voltage (DSV) PA
Direct conversion Supply Voltage Control ?
Dynamic Supply Control DSP clock speed
10MHz GaAs PA CMOS DC-DC converter SiGe
BiCMOS
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Digital Predistorer
Digital predistorter SiGe BiCMOS PA or CMOS
switching PA
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Direct RF synthesis
Direct RF Synthesis DSP clock speed 7 GHz CMOS
Switching PA and controller
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High speed Power Devices

• MESFET/ HEMT
• ? High Efficiency / high Linearity
• ? Temperature stability
• ? Negative bias ? Develop Enhancement FET
• MOSFET/LDMOS
• ? Low Efficiency
• ? Temperature Stability
• ? Single bias

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• HBT
• ? High Efficiency / High Linearity
• ? Single bias
• ? High power density
• ? Bad temperature stability
• ? introduce Ballast R, careful bias circuit

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           Fig. 1. A cross-section of IBM's SiGe
HBT structure, which was used to obtain a
record-breaking ft value of 350 GHz. Credit IBM.
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HBT comparison High power v.s. Digital
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Power transistor (FETs)
Circuit design Power combine Unit transistor
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HBT with Ballast R ( Via hole and Air bridge)
12 finger Rb50
8 finger Rb50
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Power Cell
64 finger
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MOS power cell
Conventional ??

• Conventional ??
• Poly gate? drain metal? ??? ???? ??
• Source metal? drain metal? ?? ????? Cds? ???? ??

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FET vs. HBT (size)
HBTs (being vertical in structure) consume less
die area than an equivalent FET based production
technology Examplegt take a PA line-up for GSM
(Pout35dBm, Vbat3.2V)
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Ballasting
HBT devices must be BALLASTED to ensure thermal
stability Thermal run-away is avoided if a
sufficiently large ballast resistance is placed
in either the emitter or the base of the HBT
In a multi-finger array, one device may be
hotter than other. The hotter device will
experience a drop in Vbe (-2mV/oC) which will
cause it to draw even more current from a
fixed-base-voltage supply thus it will get even
hotter. The end result is finger burn-out
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Ballasting (conti)
Three methods are available to ballast your
circuit
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HBT bias circuit
Diode-bias and current-mirror circuits can be
seen here

• The key differences are
• - Diode bias requires the diode to draw current,
  which can be significant
• Current mirror does not track as well over
  temperature
• Current mirror has the 2 ? Vbe
  reference-voltage issue

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CMOS and LDMOS power TR
IEEE EDL, Vol. 21, No.2, p81, YueTan et al.
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High power LDMOS
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Conclusions I High speed digital and analog
devices

• Submicron CMOS(0.18um) is
• covering upto 10Gbps and 10GHz range.
• Submicron CMOS(0.05um) will be
• covering upto 40 Gbps and 40 Ghz range.
• Digital part will dominate Analog and RF
• Finally, only power amp in RF with digital
  control
• will survive
• 5. LDMOSCMOS will be a winner in Power
  applications
• 6. SiGe may be used in high speed digital and
• 10-60 GHz range RF.
• 7. GaAs HBT is used in Power and Low noise
  application
• 1- 40 GHz
• 8. InP HBT and HEMT are used
• in high frequencies(above 30Ghz)

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DRAM
Figure 7.4 Simplified DRAM schematic.

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DRAM design rule
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Figure 7.7 Vertical stacked capacitor Top - SEM
photograph of the storage plate. Bottom - Solid
model and grid of the simulated structure (only
the material POLY1 is displayed).
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Figure 7.6 Process flow of the vertical stacked
capacitor.
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FINFET
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Nono MOSFET
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Quantum Dot Flash memory
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FRAM
                                         Figure
1. Schematic cross section of a FRAM unit cell
1T/1C
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Conclusion II Memory
DRAM Design rule becomes smaller,
Ferroelectric Materials make C smaller, New
Structures
Nonvolatile Memory Flash Nano-flash,
QD flash FRAM MRAM
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QWLD, QDLD
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Self-assembled QDs
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AFM image of QD
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Quantum wire grown on V groove
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LD, VCSEL, LED
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VCSEL
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Why Blue? GaN ?
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LD, LED ---Conclusion III
Laser diode QW QD ---- High power LD VCSEL
QW QD ---- Low threshold
Current
Blue light sources --- GaN Storage
illumination
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Standard Applications
Optical communication devices
Expected 10 Gigabit Ethernet solution
Distance Fiber Solution
100m installed MMF No solution. (FP laser can go 65m)
300m new MMF 850-nm VCSEL on new MMF No solution for installed MMF
2Km SMF Uncooled 1300-nm FP laser
10km SMF Uncooled, Isolated 1300-nm DFB
40km SMF Traditional telecom-style cooled Isolated, externally modulated DFB

• Method to overcome limit
• 4?2.5 Gb/s WWDM with installed MMF SMF
• 10 Gb/s TDM with SMF 1300nm LD

Ref.) Tutorials, Agilent, 2000 OE conference
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Material property of electrical device
Property of GaAs/InP HEMT at TRW
Ref) TRW and Velocium, 2002 IEEE MTT-S workshop.
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Material property of electrical device
Property of Si/GaAs/InP HBT
Ge Si GaAs InP
e- mobility (cm2/V-s) 3900 1400 8500 5400
h mobility (cm2/V-s) 1900 450 400 200
Bandgap (eV) 0.66 1.12 1.42 1.34
Thermal Cond(W/cm-C) 0.58 1.30 0.55 0.68
BVCEO vs. Ft
Ref) Inphi inc., 2002 IEEE MTT-S workshop.
TRW and Velocium, 2002 IEEE MTT-S workshop.
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Optical Rx Tx
Digital Analog IC
Ref) NTT., 2002 IEEE MTT-S workshop.
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Optical Rx Tx
Which technology is used
Pre-amp
post-amp
CDR
DeMUX
MUX
LD-Driver
PD
155Mbps
CMOS
InP
622Mbps
InP
CMOS
Si BJT
Si BJT
2.5Gbps
InP
SiGe/GaAs
CMOS
HEMT
10Gbps
SiGe/GaAs
InP
Si / SiGe
Si/SiGe
HEMT
40Gbps
InP
InP/GaAs
InP/GaAs
InP/GaAs
InP/GaAs
InP/GaAs
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Electrical package
High speed modules (40 Gbps)
40 Gbps MUX/DeMUX
40 Gbps CDRDeMUX
Clock Data Recovery 116 DeMUX With SiGe HBT,
Ball Gray package
14 DeMUX 41 MUX With InP HBT, GPPO connector
Inphi inc., 2002 IEEE MTT-S workshop.
AMCC., 2002 IEEE MTT-S workshop.
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     Fig. 2. A 100 Gbit/s selector IC fabricated
using InP-based HEMT technology. Credit NTT.
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Electrical package
High speed modules( gt 40 Gbps)
Aluminum Nitride package of NTT
Si MEMS of SOPHIA wireless
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Monolithic Integration
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                         Fig. 1. Photoreceivers
fabricated using hybrid manufacturing (a) and ELT
integration (b).
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40Gbps modules in NTT
Waveguide type PIN-TIA
The total coupled CPW lines characteristic
impedence of 50 ohm
Near Field Diameter 2 mm
WG-PD Chip
CPW line
Front end IC Chip
V-Connector
Ceramic CPW
Responsivity 0.84 0.95 A/W by two Aspherical
lenses
Cavity Resonance in PKG Housing
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Optical Communication Devices --Conclusion IV
LD Modulator High speed VCSEL
array WDM PDTIA integration TIA and
LD/Modulator Drive Optical chip set
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GaN applications
                                                
                                                  
                                                  
                                        Fig. 1.
GaN-on-silicon platform technology offers a broad
range of applications, including microelectronic
and optoelectronic products, optical sensors and
high-voltage rectifiers
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AlGaN/GaN HEMTs
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Fig. 3. Power performance of a 0.36 mm wide
AlGaN/GaN FET at 30 GHz, showing 2.3 W output
power, 38 PAE and 8.8 dB gain. Credit NEC.
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High power Transistor base station amplifier
                                                
                                                  
                                                  
           Fig. 2. Comparison of the potential
power delivered by HEMTs that have been
fabricated in GaAs, SiC and GaN.
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High power/speed devices Conclusion V
LDMOS MESFET SiC MESFET/MOSFET GaN HEMT
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Display devices --- Organic LED
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Conclusion-VI
Display LCD OLED CRT
Plasma Projection LED
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Conclusions
Conclusion I --- high speed digital
analog Conclusion II --- high density
memory Conclusion III ---LD,LED Conclusion IV
---Optical communication device Conclusion V ---
high voltage Conclusion VI--- dispaly