I Dr. Gerhard Klimeck
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Edward Stone Award for Outstanding Publication Seminars Computational Nanoelectronics Towards: Design, Analysis, Synthesis, and Fundamental Limits I 180/101 Dr. Gerhard Klimeck Q 0 10 20 30 40 50 60 Position (nm) Technical group supervisor of the Applied Cluster Computing Technologies Group and a Principal member at the Jet Propulsion Laboratory Nanotechnology and Nanoelectronics in particular have received a lot of public attention since President Clinton announced a National Nanotechnology Initiative at Caltech. Nanotechnology bears the promise to provide new approaches to electronics, materials, medicine, biology and a variety of other technologies. In the world of semiconductor electronics, nanotechnology has already arrived in practical devices. Wave-like properties of electrons modify the functional device behavior once spatial variations in structures reach length scales of a few tens of nanometers. While standard technologies require extensive simulation tools for design, analysis and characterization, no such tools exist for nanoelectronic devices. The modeling and simulation of such devices now deviates strongly from classical approaches: it must be fundamentally quantum mechanical. JPL has been involved in nanoelectronic modeling since 1998 following efforts started at Texas Instrument in 1993. This seminar will review the development of a comprehensive nanoelectronic modeling tool (NEMO 1-D and NEMO 3-D) and its application to high-speed electronics (resonant tunneling diodes) and IR detectors and lasers (quantum dots and 1-D heterostructures). 0cn I- .-6 m C 8 U 0 a, v) a, cCI .- .L a a a L .-mi a> 1 120 0 -E m C s 3 S nf m 0 3 > E YI m 0 m nS 0 C 3 I m- LL O 9 % . US 0 m m .s m O .-S E 0- E E rW i= I >s s II € 0 W F a> US LL3 JPL Presentation Outline Introduction / Motivation Nan0 device needs, modeling needs. Critical look at the SIA Roadmap. ID heterostructure modeling Ba nds t ruct ure eng inee ri ng basics . Resonant tunneling diodes Hole transport (Ed Stone Award). "EM0 I-D - First quantum device simulator. 3D heterostructure modeling NEMO 3-D Modeling agenda. .What is a quantum dot? .Quantum dot examples. *Alloy disorder in quantum dots. Analysis and Synthesis using Genetic Algorithms (GAS) GA basics Design Synthesis Conclusion / Outlook Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Motivation Our enthusiasm for Nano- technology stems from its potential value in addressing Deep Space technology needs: 4 Autonomous navigation and maneuvering, 4 Miniature in-situ sensors, 4 Radiation and temperature tolerant electronics. Nano-technology will provide essential computing and sensing capabilities. c Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Near Term Example Application Quantum Dots for Optoelectronic Devices InGaAsSb/GaSb InGaAsP/InP Quantum Cascade Diode Sources CH, NO2 HF HCL HN(’3 03 CIO Atmospheric Gases I 31 I I NH3 C2H2 H2p I JPL Need for Nanoelectronic Simulation Problems: Design space is huge Simulation Choice of materials, shapes, orientations, dopings, heat anneals Characterizations are incomplete and invasive / destructive Simulation Impact: *Aide Design Fast, cost effective. -> Device performance successful for 1 -D quantum devices Aide Characterization Non-invasive More accurate Characterization Fabrication =>Structure and doping analysis Q 03 t LI rI n.. I a, 03 cn cn>a S a,r S 0 -cIL 0 0 .--cI S 0 -a, mN .-CI .- \a, L 0 3 .Im - L 2 .- 0 Sm n -cI .- rcm E m CIa, .-0a, a, > cnt a, .- U0 n0 .I 1 0 0 0 JPL Technology Push Toward Fundamental Limitations CommerciaI market pushes I computing (FLOPS/weight/power): Enabled by odevice miniaturization .chip size increase 0 Limited by: Costs of fabrication *Discrete atoms/electrons Add iti o na I NASA Requ i reme n ts : 0 High radiation tolerance 1990 0 Extreme temperature operation- -"d80 2000 2010 : 0: - hot/coId L 2-D Lithograp feature 1 I-D feature t5-100 I A L / Gerhard Klimeck Applied Cluster Computing Technologies Group I Technology Push I Toward Fundamental Limitations - ~ Commercial market pushes Number of Electrons I computing (FLOPS/weight/power): 1 o4 e2 kT >> - Enabled by 2c .device min iat u rization E1 .c,2 o3 .chip size increase -8 W Limited by: Y-10 u2 Costs of fabrication 3 ODiscrete atomslelectrons 51 0' e2 : z kT << - Add it iona I NASA Requ i remen ts 2c High radiation tolerance 1oo Extreme temperature operation- 1980 1990 2000 2010 2020 hotlcold 2-D Lithography feature c 1 l=D 3 feature L0 t5-700 A (3 L Gerhard Klimeck Applied Cluster Computing Technologies Group JPL I Technology Push Toward Fundamental Limitations ~ Commercial market pushes .-e2 2c -- e2 2c hotfcold 2-D Lithography - feature JPL Presentation Outline Introduction / Motivation *Nan0 device needs, modeling needs. *Critical look at the SIA Roadmap. ID heterostructure modeling Bandst ruct ure engineering basics . Resonant tunneling diodes Hole transport (Ed Stone Award). *NEMO 1-D - First quantum device simulator. 3D heterostructure modeling NEMO 3=D Modeling agenda. *What is a quantum dot? *Quantum dot examples. *Alloy disorder in quantum dots. Analysis and Synthesis using Genetic Algorithms (GAS) GA basics Design Synthesis Conclusion I Outlook Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Bandstructure Basics Electron Conduction in Solids Physics t Transport conductivity, mobility Devices Bands are channels in which electrons move “freely”. Layers of different atoms are deposited with monolayer control. We can engineer the electron bands. L Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Bandstructure Engineering Basics I Resonance Energies / Eigenvalues - --- - --I r -- -r - -I I Barriers and Wells Wave Functions / Eigenstates Layers with different band alignments 0 0 + & Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Bandstructure Engineering Basics Resonance Energies / Eigenvalues L Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Bandstructure Engineering Applications Transitions / Transport Photon Photon Absorption Emission Tunneling c Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Bandstructure Engineering Applications Transitions / Transport - -1- I-- -n- - -- r Photon 1__1 Absorption Detectors I Quantum Well Infrared Detector \ Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Bandstructure Engineering Applications Transi :ions / Transport -1--- -1--- I Photon Emission 1 Lasers -1,or:::::::::::i 0 10 20 30 40 50 60 Position (nm) Quantum Cascade L Laser Gerhard Klimeck Ap pI ied C Ius te r Comput i ng Techno Iog ies G roup JPL Bandstructure Engineering Applications ---rTransitions / Trans 30t-t Tunneling Logic I Memory n 4Resonant Tunneling Diode Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Transitions / Transport Controlled by Desi Photon Absorption Emission Tunneling 1 Detectors Lasers Logic I Memory i 2.0 57 10 J 5r S UJF 00 9 40 tiis 88 2i5 qm 0 10 20 30 40 50 60 P @W Position (rim) Resonant Quantum Well Quantum Cascade Tunneling Infrared Detector Laser Diode L Gerhard Klimeck Applied Cluster Computing Technologies Group Sb1780 Sb 1781 R=8.8R Nominal Size 07/20/07 ml I I I I I 4 EXP o 1 108/17/0L8 - 1 0 0.2 0.4 0.6 0.8 1 1.2 Applied Bias (V) 12 different I-V curves: 2 wafers, 3 mesa sizes, 2 bias directions Voltage 50nm le18 InGaAs 7 ml nid InGaAs 7 ml nid AlAs m 20 ml nid InGaAs Conduction band diagrams 7 mi nid AlAs for different voltages 7 ml nid InGaAs and the resulting current flow. 50 nm le18 InGaAs JPL Testmatrix-Based Verification (room temperature) Strained InGaAs/AIAs 4 Stack RTD with Asymmetric Barrier Variation V744 #I, Nom.: 07/17/07 ml, Sim.: 09/18/09 ml V744 #2, Nom.: 07/17/08 ml, Sim.: 09/18/10 ml 18000 I I Forw. Bias - 16000 CJ 14000 Rev. Bias - Simulation 12000 - x .G2 10000 CI ----- *g 8000 3 8000 a 8 hnnn---- c ffl i i -8 6000 c 4000 4000 s9 s9 " 2000 5 2000 HG HG n" 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 - Applied Bias (V) Applied Bias (V) 20/50/ 2 744 #3, Nom.: 07/17/09 ml, Sim.: 09/18/11 ml 744 #4, Nom.: 07/17/10 ml, Sim.: 09/18/12 ml 9000 I I I I I /1 9000 I I I I I I h 8000 Fonv. Bias -- Four increasingly CJ 8000 Simulation -+- 7000 Simulation asymmetric Rev. Bias Rev. Bias - 6000 Simulation .....)........... devices : 2A x et: 5000 s 5000 20/50/20 Angstrom 2 92 & 4000 & 4000 20/50/23 Angstrom 3000 'S0 3000 20/50/25 Angstrom 2 2000 5 2000 20/50/27 Angstrom u 1000 u 1000 0 0 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 Applied Bias (V) Applied Bias (V) Presented at IEEE DRC 1997, work performed at Texas Instrument. Dallas Gerhard Klimeck Applied Cluster Computing Technologies Group JPL Presentation Outline Introduction / Motivation .Nan0 device needs, modeling needs. .Critical look at the SIA Roadmap. 1D heterostructure modeling Bandstructure engineering basics. Resonant tunneling diodes Hole transport (Ed Stone Award). NEMO 1-D - First quantum device simulator. 3D heterostructure modeling NEMO 3-D Modeling agenda. .What is a quantum dot? .Quantum dot examples. .Alloy disorder in quantum dots. .Analysis and Synthesis using Genetic Algorithms (GAS) GA basics Design Synthesis Conclusion / Outlook Gerhard Klimeck Applied Cluster Computing Technologies Group 4c 20 Electron Density of States and Transmission Coefficients 30I I I1 5 25 0-f 10" 1 0-1 2.0 Trmsrnissi on JPL I @>I Hole Density of States and ..-. 2=- Transmission Coefficients Gerhard Klimeck Applied Cluster Computing Technologies Grou 3 JPL Hole Transport in a GaAs/AIAs RTD - HH1 -';--LKZ .5 1 1 10- 10' 1 Light hole states strongly coupled to continuum -> wide resc Heavy hole states weaklv cowled to continuum->narrow Gerhard Klimeck Applied Cluster Computing Technologies Group Electron vs.