Future devices for Information Technology

2003. 4. 4.

Songcheol Hong

Contents

Electronic Devices (processing devices)High speed devices(digital, analog, RF)High power devicesMemory devices

Optical Devices QWLD, QDLD

Optical communication devicesGaN based Devices

Display

High speed devicesHigh 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)

Bias control Supply voltage

control

DSP SDR

One Chip Radio

ACPR(dBc)

DSVPA

AverageEfficiency(%)

Year2000 2003 2006 2009

0

40

60

80

SmartPA -45

-50

-55

2012

20

DigitalPredistor

Direct RFSynthesis

Smart PAHeterodyne type

Base/gate bias voltage control

GaAs based PA

DACIin

Qin

VCO1

IF VGA

VCO2

Up-Mixer

PARFout

Gate/base bias control

Dynamic supply voltage (DSV) PADirect conversion

Supply Voltage Control Dynamic Supply Control

DSP clock speed ~ 10MHz

GaAs PA + CMOS DC-DC converter SiGe BiCMOS

DAC & ADCcontroller

Iin

Qin

RFoutPA

BiasController

VCO

Digital PredistorerDigital predistorter

SiGe BiCMOS PA or CMOS switching PA

RFoutPA

BiasController

VCO

DAC & ADCcontroller

Iin

Qin

Digitalpre-

distorter

Amplitude

Phase

Direct RF synthesisDirect RF Synthesis

DSP clock speed ~ 7 GHz

CMOS Switching PA and controller

Digital Phase &Amplitude Mod.

Iin

Qin

Phase

Amplitude/Ramping

RFoutSynthesizer/

VCO

AmplitudeModulator

SwitchingPA

RFoutIin

Qin Filter

SwitchingPA

BandpassDelta-SigmaModulator

DSP

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

•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 ft value of 350 GHz. Credit: IBM.

HBT comparison High power v.s. Digital

Circuit design : Power combine : Unit transistor

Power transistor (FETs)

HBT with Ballast R ( Via hole and Air bridge)

8 finger Rb=50

12 finger Rb=50

Power Cell64 finger

Conventional 구조(1) Poly gate 와 drain metal 의 저항이 클것으로 예상(2) Source metal 이 drain metal 을 덮는 구조이므로 Cds 가 클것으로 예상

Conventional 구조MOS power cell

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/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

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 devices1. 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 RF4. Finally, only power amp in RF with digital control

will survive5. LDMOS+CMOS will be a winner in Power applications6. 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 GHz8. InP HBT and HEMT are used in high frequencies(above 30Ghz)

Figure 7.4: Simplified DRAM schematic.

DRAM

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

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

FRAM

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

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

Quantum wire grown on V groove

LD, VCSEL, LED

VCSEL

Why Blue? GaN ?

LD, LED ---Conclusion IIILaser diode

QWQD ---- High power LD

VCSEL

QW QD ---- Low threshold Current

Blue light sources --- GaN

Storage illumination

Ref.) Tutorials, Agilent, 2000 OE conference

Distance Fiber Solution100m installed MMF No solution. (FP laser can go 65m)

300m new MMF850-nm VCSEL on new MMFNo 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 42.5 Gb/s WWDM with installed MMF & SMF 10 Gb/s TDM with SMF & 1300nm LD

Expected 10 Gigabit Ethernet solution

Standard & ApplicationsOptical communication devices

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

Property of GaAs/InP HEMT at TRW

Material property of electrical device

BVCEO vs. Ft

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

Ge Si GaAs InP

e- mobility (cm2/V-s) 3900 1400 8500 5400h+ mobility (cm2/V-s) 1900 450 400 200Bandgap (eV) 0.66 1.12 1.42 1.34Thermal Cond(W/cm-C) 0.58 1.30 0.55 0.68

Property of Si/GaAs/InP HBT

Material property of electrical device

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

Optical Rx & Tx

Digital & Analog IC

Optical Rx & Tx

Which technology is used

Pre-amp

155Mbps CMOS

622Mbps

2.5Gbps

10Gbps

40Gbps

post-amp CDR DeMUX MUX LD-Driver

SiGe/GaAs

PD

InP

InP InP/GaAs

Si / SiGe Si/SiGe HEMT

InP

InP

InP

CMOSSi BJT

InP/GaAs InP/GaAs InP/GaAs InP/GaAs

SiGe/GaAs CMOS

Si BJT

HEMT

40 Gbps MUX/DeMUX

Inphi inc., 2002 IEEE MTT-S workshop. AMCC., 2002 IEEE MTT-S workshop.

40 Gbps CDR+DeMUX1:4 DeMUX 4:1 MUX

With InP HBT, GPPO connector

Clock Data Recovery

1:16 DeMUX

With SiGe HBT, Ball Gray package

Electrical package

High speed modules (40 Gbps)

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

Aluminum Nitride package of NTT Si MEMS of SOPHIA wireless

Electrical package

High speed modules( > 40 Gbps)

AGERE SYSTEMTunable EML Module- SOA Integrated- 2-Section DBR- Front PD Integrated

Monolithic IntegrationMonolithic Integration

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

WG-PD ChipWG-PD Chip

Responsivity : 0.84 ~ 0.95 A/Wby two Aspherical lenses

The total coupled CPW lines : characteristic impedence of 50 ohm

CPW line

Front end IC Chip

Ceramic CPW

V-Connector

Near Field Diameter : 2 m

Cavity Resonance in PKG Housing

40Gbps modules in NTT40Gbps modules in NTTWaveguide type PIN-TIA

Optical Communication Devices --Conclusion IVLD + Modulator High speed VCSEL arrayWDM

PD+TIA integration

TIA and LD/Modulator Drive

Optical chip set

Fig. 1. GaN-on-silicon platform technology offers a broad range of applications, including microelectronic and optoelectronic products, optical sensors and high-voltage rectifiers

GaN applications

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

Figure 1

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.

Fig. 2. Comparison of the potential power delivered by HEMTs that have been fabricated in GaAs, SiC and GaN.

High power Transistor– base station amplifier

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