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Three-Dimensional Metal-Semiconductor Heterostructures for Device Applications

Wernersson, Lars-Erik LU (1998)
Abstract
Fabrication and characterisation of buried metal contacts in compound semiconductors are demonstrated. The contacts have been investigated due to their usage both as gates in transistors and as active or passive elements in novel devices.



A detailed description of the processing conditions for fabrication of nm-sized W-structures in a lift-off process is given. These structures have been embedded in GaAs or InP by epitaxial overgrowth using metalorganic vapour phase epitaxy. The conditions for epitaxial overgrowth are discussed and a special emphasis is given the correlation between processing and electrical characteristics of the buried contacts.



Matrices of W discs have been buried in GaAs and a... (More)
Fabrication and characterisation of buried metal contacts in compound semiconductors are demonstrated. The contacts have been investigated due to their usage both as gates in transistors and as active or passive elements in novel devices.



A detailed description of the processing conditions for fabrication of nm-sized W-structures in a lift-off process is given. These structures have been embedded in GaAs or InP by epitaxial overgrowth using metalorganic vapour phase epitaxy. The conditions for epitaxial overgrowth are discussed and a special emphasis is given the correlation between processing and electrical characteristics of the buried contacts.



Matrices of W discs have been buried in GaAs and a controlled formation of semi-insulating material is demonstrated in structures with varying disc separation. The kinetics of the buried contacts have been investigated by photo-conductivity measurements, photo-capacitance transients and deep-level transient spectroscopy (DLTS). The capture and emission have been studied on a signal level of one electron per disc. Thereby, the Coulomb effect on the contacts are revealed.



The semi-insulating properties is used for fabrication of vertical channels in vacant postitions in a buried disc lattice. GaInP/GaAs double barriers are combined with the buried metal discs and sub-micrometer resonant tunnelling diodes are created.



Three-terminal devices are further discussed. The characteristics of a Heterojunction Permeable Base Transistor has been simulated and the ballistic transport is shown to substantially enhance the device performance. Interference of electron waves is numerically demonstrated to create an interference pattern in the Solid State Biprism Device. Finally, lateral confinement effects are observed in a resonant tunnelling transistor. All these devices rely on the fabrication of three-dimensional metal-semiconductor heterostructures. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof Palmstrom, C., University of Minnesota, Minnesota, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Schottky contacts, space-charge spectroscopy, ballistic transport, Coulomb repulsion, electron interference, resonant tunnelling, lateral confinement, heterojunction permeable base transistor, resonant tunnelling diodes, Fysicumarkivet A:1998:Wernersson, Fysik, Physics, resonant tun, epitaxial overgrowth
pages
182 pages
publisher
Lars-Erik Wernersson Norbergsg. 3 223 54 Lund,
defense location
Foerelaesningssal B Fysiska Institutionen
defense date
1998-05-26 10:15
external identifiers
  • Other:LUFTD2/(TFFF-0051)/1-182
ISBN
91-628-3002-3
language
English
LU publication?
yes
id
eea86850-a0e8-4cbb-87f0-f86eed2cb353 (old id 38697)
date added to LUP
2007-10-02 16:04:35
date last changed
2016-09-19 08:45:07
@phdthesis{eea86850-a0e8-4cbb-87f0-f86eed2cb353,
  abstract     = {Fabrication and characterisation of buried metal contacts in compound semiconductors are demonstrated. The contacts have been investigated due to their usage both as gates in transistors and as active or passive elements in novel devices.<br/><br>
<br/><br>
A detailed description of the processing conditions for fabrication of nm-sized W-structures in a lift-off process is given. These structures have been embedded in GaAs or InP by epitaxial overgrowth using metalorganic vapour phase epitaxy. The conditions for epitaxial overgrowth are discussed and a special emphasis is given the correlation between processing and electrical characteristics of the buried contacts.<br/><br>
<br/><br>
Matrices of W discs have been buried in GaAs and a controlled formation of semi-insulating material is demonstrated in structures with varying disc separation. The kinetics of the buried contacts have been investigated by photo-conductivity measurements, photo-capacitance transients and deep-level transient spectroscopy (DLTS). The capture and emission have been studied on a signal level of one electron per disc. Thereby, the Coulomb effect on the contacts are revealed.<br/><br>
<br/><br>
The semi-insulating properties is used for fabrication of vertical channels in vacant postitions in a buried disc lattice. GaInP/GaAs double barriers are combined with the buried metal discs and sub-micrometer resonant tunnelling diodes are created.<br/><br>
<br/><br>
Three-terminal devices are further discussed. The characteristics of a Heterojunction Permeable Base Transistor has been simulated and the ballistic transport is shown to substantially enhance the device performance. Interference of electron waves is numerically demonstrated to create an interference pattern in the Solid State Biprism Device. Finally, lateral confinement effects are observed in a resonant tunnelling transistor. All these devices rely on the fabrication of three-dimensional metal-semiconductor heterostructures.},
  author       = {Wernersson, Lars-Erik},
  isbn         = {91-628-3002-3},
  keyword      = {Schottky contacts,space-charge spectroscopy,ballistic transport,Coulomb repulsion,electron interference,resonant tunnelling,lateral confinement,heterojunction permeable base transistor,resonant tunnelling diodes,Fysicumarkivet A:1998:Wernersson,Fysik,Physics,resonant tun,epitaxial overgrowth},
  language     = {eng},
  pages        = {182},
  publisher    = {Lars-Erik Wernersson Norbergsg. 3 223 54 Lund,},
  school       = {Lund University},
  title        = {Three-Dimensional Metal-Semiconductor Heterostructures for Device Applications},
  year         = {1998},
}