Future devices for Information Technology

2003. 4. 4.

Songcheol Hong

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

High speed devices

Digital, Analog(RF) DSP upto Microwave frequencies IEEE MTT Vol. 50, N0. 3, 2002 p900

Power dissipation/ MIPS

Digital circuits expands to Analog domain

Trends in Transmitter Architecture(Mobile) DC-DC converter Vector Modulator High Speed DSP (7GHz) 80 Average Efficiency(%) 60 Direct RF Synthesis ACPR (dBc) -55 40 Digital Predistor DSV PA -50 20 0 Smart PA -45 2000 Bias control 2003 2006 Supply voltage control DSP 2009 SDR Year 2012 One Chip Radio

Smart PA

Heterodyne type Base/gate bias voltage control GaAs based PA

Gate/base bias control

IF VGA Up-Mixer I in Q in DAC PA RFout VCO1 VCO2

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 Bias Controller I in Q in DAC & ADC controller PA RFout VCO

Digital Predistorer

Digital predistorter SiGe BiCMOS PA or CMOS switching PA I in Q in Amplitude DAC & ADC controller Digital pre distorter Phase Bias Controller PA RFout VCO

Direct RF synthesis

Direct RF Synthesis DSP clock speed ~ 7 GHz CMOS Switching PA and controller I in Q in I in Q in Bandpass Delta-Sigma Modulator DSP Switching PA Digital Phase & Amplitude Mod.

Amplitude /Ramping Phase Synthesizer/ VCO Amplitude Modulator Switching PA RFout Filter RFout

High speed Power Devices

• MESFET/ HEMT

 High Efficiency / high Linearity  Temperature stability  Negative bias Enhancement FET  Develop

• MOSFET/LDMOS

 Low Efficiency  Temperature Stability  Single bias

•HBT

 High Efficiency / High Linearity  Single bias  High power density  Bad temperature stability  introduce Ballast R, careful bias circuit

Typical InGaP Emitter HBT Structure

Fig. 1. A cross-section of IBM's SiGe HBT structure, which was used to obtain a record-breaking f t value of 350 GHz. Credit: IBM.

HBT comparison High power v.s. Digital

Power transistor (FETs)

Circuit design : Power combine : Unit transistor

HBT with Ballast R ( Via hole and Air bridge) 12 finger Rb=50 8 finger Rb=50

Power Cell

64 finger

MOS power cell

Conventional 구조  Conventional 구조 (1) Poly gate와 drain metal의 저항이 클 것으로 예상 (2) Source metal이 drain metal을 덮는 구조이므로 Cds가 클것으로 예상

FET vs. HBT (size) HBT’s (being vertical in structure) consume less die area than an equivalent FET based production technology Example> take a PA line-up for GSM (Pout=35dBm, Vbat=3.2V)

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/ o C) 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

Ballasting (conti

…

) • Three methods are available to ballast your circuit

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

CMOS and LDMOS power TR IEEE EDL, Vol. 21, No.2, p81, YueTan et al.

High power LDMOS

Conclusions I High speed digital and analog devices 1. Submicron CMOS(0.18um) is covering upto 10Gbps and 10GHz range.

2. Submicron CMOS(0.05um) will be covering upto 40 Gbps and 40 Ghz range. 3. Digital part will dominate Analog and RF 4. Finally, only power amp in RF with digital control will survive 5. LDMOS+CMOS 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)

DRAM Figure 7.4: Simplified DRAM schematic.

DRAM design rule

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).

Figure 7.6: Process flow of the vertical stacked capacitor.

FINFET

Nono MOSFET

Quantum Dot Flash memory

FRAM Figure 1. Schematic cross section of a FRAM unit cell [1T/1C]

Conclusion II Memory DRAM: Design rule becomes smaller, Ferroelectric Materials make C smaller, New Structures Nonvolatile Memory: Flash Nano-flash, QD flash FRAM MRAM

QWLD, QDLD

Self-assembled QDs

AFM image of QD

Quantum wire grown on V groove Figure 2. TEM micrograph showing the core of a 5-QWR Laser. The wires are positioned inside the 2D optical waveguide in an asymmetric configuration in order to maximize the overlap of the optical mode with

LD, VCSEL, LED

VCSEL

Why Blue? GaN ?

LD, LED ---Conclusion III Laser diode QW QD ---- High power LD VCSEL QW QD ---- Low threshold Current Blue light sources --- GaN Storage illumination

Expected 10 Gigabit Ethernet solution Distance

100m 300m 2Km 10km 40km

Fiber installed

MMF

new

MMF SMF SMF SMF

Solution

No solution. (FP laser can go 65m) 850-nm VCSEL on

new

MMF No solution for installed MMF Uncooled 1300-nm FP laser Uncooled, Isolated 1300-nm DFB 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

Material property of electrical device Property of GaAs/InP HEMT at TRW

Ref) TRW and Velocium, 2002 IEEE MTT-S workshop.

Material property of electrical device Property of Si/GaAs/InP HBT e- mobility (cm 2 /V-s) h+ mobility (cm 2 /V-s) Bandgap (eV) Thermal Cond(W/cm-C) Ge 3900 1900 0.66

0.58

Si 1400 450 1.12

1.30

GaAs 8500 400 1.42

0.55

InP 5400 200 1.34

0.68

BVCEO vs. Ft

Ref) Inphi inc., 2002 IEEE MTT-S workshop.

TRW and Velocium, 2002 IEEE MTT-S workshop.

Optical Rx & Tx Digital & Analog IC

Ref) NTT., 2002 IEEE MTT-S workshop.

Optical Rx & Tx Which technology is used

155Mbps 622Mbps 2.5Gbps

10Gbps 40Gbps PD InP InP Pre-amp post-amp Si BJT InP InP SiGe/GaAs InP SiGe/GaAs InP/GaAs CDR CMOS DeMUX CMOS CMOS Si / SiGe InP/GaAs InP/GaAs MUX Si/SiGe InP/GaAs LD-Driver Si BJT HEMT HEMT InP/GaAs

Electrical package High speed modules (40 Gbps) 40 Gbps MUX/DeMUX 1:4 DeMUX 4:1 MUX With InP HBT, GPPO connector 40 Gbps CDR+DeMUX Clock Data Recovery 1:16 DeMUX With SiGe HBT, Ball Gray package Inphi inc., 2002 IEEE MTT-S workshop.

AMCC., 2002 IEEE MTT-S workshop.

Fig. 2. A 100 Gbit/s selector IC fabricated using InP-based HEMT technology. Credit: NTT.

Electrical package High speed modules( > 40 Gbps) Aluminum Nitride package of NTT Si MEMS of SOPHIA wireless

Monolithic Integration

AGERE SYSTEM Tunable EML Module - SOA Integrated - 2-Section DBR - Front PD Integrated

Fig. 1. Photoreceivers fabricated using hybrid manufacturing (a) and ELT integration (b).

40Gbps modules in NTT

Waveguide type PIN-TIA Near Field Diameter : 2

m

m The total coupled CPW lines : characteristic impedence of 50 ohm WG-PD Chip CPW line Front end IC Chip Responsivity : 0.84 ~ 0.95 A/W by two Aspherical lenses Cavity Resonance in PKG Housing Ceramic CPW V-Connector

Optical Communication Devices --Conclusion IV LD + Modulator High speed VCSEL array WDM PD+TIA integration TIA and LD/Modulator Drive Optical chip set

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

AlGaN/GaN HEMTs

Fig. 1. A typical layer structure used for the fabrication of AlGaN/GaN HEMTs

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.

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.

High power/speed devices Conclusion V LDMOS MESFET SiC MESFET/MOSFET GaN HEMT

Display devices --- Organic LED

Conclusion-VI Display LCD OLED CRT Plasma Projection LED

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