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Tunneling Based Electronic Devices

Lind, Erik LU (2004)
Abstract (Swedish)
Popular Abstract in Swedish

Denna avhandling behandlar design, tillverkning, karakterisering och optimering av elektroniska komponenter alla baserade på kvantmekanisk tunnling.



Tunnling är ett rent kvantmekaniskt fenomen utan någon klassisk motsvarighet, som först blir relevant då dimensionerna krymper ner i nanometerskala (en nanometer är en miljarddel's meter). Då kan elektroner ”tunnla” igenom barriärer vilka i klassisk fysik hade stoppat dera's framfart. Det innebär bland annat, att material som är elektriska isolatorer i makroskopiska storlekar kan börja släppa igenom ström när de krymp's ner till nanometerskalan. Tunnlingsfenomenet kan vidare använda's för att tillverka komponenter som uppvisar... (More)
Popular Abstract in Swedish

Denna avhandling behandlar design, tillverkning, karakterisering och optimering av elektroniska komponenter alla baserade på kvantmekanisk tunnling.



Tunnling är ett rent kvantmekaniskt fenomen utan någon klassisk motsvarighet, som först blir relevant då dimensionerna krymper ner i nanometerskala (en nanometer är en miljarddel's meter). Då kan elektroner ”tunnla” igenom barriärer vilka i klassisk fysik hade stoppat dera's framfart. Det innebär bland annat, att material som är elektriska isolatorer i makroskopiska storlekar kan börja släppa igenom ström när de krymp's ner till nanometerskalan. Tunnlingsfenomenet kan vidare använda's för att tillverka komponenter som uppvisar negativ differentiell resistan's, det vill säga komponenter i vilka strömmen minskar då spänningen ökar. Denna karakteristik är intressant för olika elektroniska tillämpningar, till exempel oscillatorer och kompakt integration av digitala grindar.



Två sådana komponenter har studerat's här, så kallade resonanta tunneldioder och Esaki-dioder. Genom avancerad halvledarprocessning är det vidare möjligt att tillverka tre-terminalkomponenter, så kallade transistorer. På så sätt kan man även tillverka tunneltransistorer, i vilka tunnelströmmen kan styra's med en yttre pålagd kontrollspänning. Avhandlingsarbetet täcker fabrikation av resonanta tunneltransistorer, design av resonanta tunneldioder/transistorer för höghastighetstillämpningar, och tredimensionell integration av metaller och halvledare. Även grundläggande studier transportmekanismer för kopplade lågdimensionella system har utfört's, där elektroner tunnlar mellan två noll-dimensionella tillstånd.. Slutligen har Esaki-dioder i kisel-germanium lämpade för integration med traditionell kiselbaserad elektronik tillverkat's. (Less)
Abstract
This thesis concerns different kinds of tunneling based devices all showing negative differential resistance. The thesis is divided in three parts, resonant tunneling transistors, Esaki diodes and coupled zero dimensional systems.



The resonant tunneling transistors are GaAs-based vertical field effects transistors, based on a combination of overgrown tungsten gates and double barrier heterostructures. The gate is placed in direct vicinity of the heterostructure, and due to Schottky depletion around the gate the effective conducting area of the heterostructure can be controlled. Transistors based on two different double barriers have been investigated, GaAs0.3P0.7 and Al0.8Ga0.2As/GaAs/In0.2Ga0.8As. The GaAsP-system were... (More)
This thesis concerns different kinds of tunneling based devices all showing negative differential resistance. The thesis is divided in three parts, resonant tunneling transistors, Esaki diodes and coupled zero dimensional systems.



The resonant tunneling transistors are GaAs-based vertical field effects transistors, based on a combination of overgrown tungsten gates and double barrier heterostructures. The gate is placed in direct vicinity of the heterostructure, and due to Schottky depletion around the gate the effective conducting area of the heterostructure can be controlled. Transistors based on two different double barriers have been investigated, GaAs0.3P0.7 and Al0.8Ga0.2As/GaAs/In0.2Ga0.8As. The GaAsP-system were used for low temperature operation, whereas the AlGaAs was optimized for room temperature functionality. For resonant tunneling diode structures, a peak current density of 70 kA/cm2, a peak-to-valley ratio of 4 with a peak voltage of 0.3V was obtained, all at room temperature. The transistors has a simultaneously a maximum transconductance gm=120 mS/mm, and a peak-to-valley ratio of 2.5. Further on, a transistor based on three dimensional integration of two resonant tunnel diodes and a single metallic gate has been demonstrated.



The same technology has also been used to fabricate structures for coupled low dimensional systems. Studies of transport between a single impurity and an electrostatically defined quantum dot were preformed at a temperature T=0.3 K and B-fields up to 12 T. The resulting data shows that the angular momentum of the electrons are conserved during the tunneling event.



SiGe Esaki Tunnel Diodes has been fabricated using a combined approach of ultra high vacuum chemical vapor deposition epitaxial growth and proximity rapid thermal diffusion. This process is suitable for integration of tunnel diodes with mainstream SiGe-technology. The diodes shows a peak current density of 0.18 kA/cm2 and a peak-to-valley ratio of 2.6 at room temperature. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Lüth, Hans, Forschungszentrum Jülich, Germany
organization
publishing date
type
Thesis
publication status
published
subject
keywords
SiGe, Esaki Diodes, classical mechanics, quantum mechanics, relativity, termodynamik, relativitet, kvantmekanik, statistisk fysik, Matematisk och allmän teoretisk fysik, thermodynamics, gravitation, statistical physics, GaAs, Mathematical and general theoretical physics, Resonant Tunneling Permeable Base Transistors, Resonant Tunneling Diodes, klassisk mekanik, Fysicumarkivet A:2004:Lind
pages
126 pages
publisher
Solid State Physics, Lund University
defense location
Lecture hall B, Dept of Physics, Sölvegatan 14, Lund Institute of Technology
defense date
2004-11-05 13:15
ISBN
91-628-6226-X
language
English
LU publication?
yes
id
a5f06e53-7aee-4c62-a049-4e60c8e63c7a (old id 467491)
date added to LUP
2007-09-28 11:21:20
date last changed
2016-09-19 08:45:07
@phdthesis{a5f06e53-7aee-4c62-a049-4e60c8e63c7a,
  abstract     = {This thesis concerns different kinds of tunneling based devices all showing negative differential resistance. The thesis is divided in three parts, resonant tunneling transistors, Esaki diodes and coupled zero dimensional systems.<br/><br>
<br/><br>
The resonant tunneling transistors are GaAs-based vertical field effects transistors, based on a combination of overgrown tungsten gates and double barrier heterostructures. The gate is placed in direct vicinity of the heterostructure, and due to Schottky depletion around the gate the effective conducting area of the heterostructure can be controlled. Transistors based on two different double barriers have been investigated, GaAs0.3P0.7 and Al0.8Ga0.2As/GaAs/In0.2Ga0.8As. The GaAsP-system were used for low temperature operation, whereas the AlGaAs was optimized for room temperature functionality. For resonant tunneling diode structures, a peak current density of 70 kA/cm2, a peak-to-valley ratio of 4 with a peak voltage of 0.3V was obtained, all at room temperature. The transistors has a simultaneously a maximum transconductance gm=120 mS/mm, and a peak-to-valley ratio of 2.5. Further on, a transistor based on three dimensional integration of two resonant tunnel diodes and a single metallic gate has been demonstrated.<br/><br>
<br/><br>
The same technology has also been used to fabricate structures for coupled low dimensional systems. Studies of transport between a single impurity and an electrostatically defined quantum dot were preformed at a temperature T=0.3 K and B-fields up to 12 T. The resulting data shows that the angular momentum of the electrons are conserved during the tunneling event.<br/><br>
<br/><br>
SiGe Esaki Tunnel Diodes has been fabricated using a combined approach of ultra high vacuum chemical vapor deposition epitaxial growth and proximity rapid thermal diffusion. This process is suitable for integration of tunnel diodes with mainstream SiGe-technology. The diodes shows a peak current density of 0.18 kA/cm2 and a peak-to-valley ratio of 2.6 at room temperature.},
  author       = {Lind, Erik},
  isbn         = {91-628-6226-X},
  keyword      = {SiGe,Esaki Diodes,classical mechanics,quantum mechanics,relativity,termodynamik,relativitet,kvantmekanik,statistisk fysik,Matematisk och allmän teoretisk fysik,thermodynamics,gravitation,statistical physics,GaAs,Mathematical and general theoretical physics,Resonant Tunneling Permeable Base Transistors,Resonant Tunneling Diodes,klassisk mekanik,Fysicumarkivet A:2004:Lind},
  language     = {eng},
  pages        = {126},
  publisher    = {Solid State Physics, Lund University},
  school       = {Lund University},
  title        = {Tunneling Based Electronic Devices},
  year         = {2004},
}