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GaN-based Schottky diodes: a study of ideality factor and barrier height / submitted by Tamara C. Decker
AutorInnenDecker, Tamara
Beurteiler / BeurteilerinBonanni, Alberta ; Müh, Frank
ErschienenLinz, 2018
Umfangx, 87 Seiten : Illustrationen
HochschulschriftUniversität Linz, Masterarbeit, 2018
Schlagwörter (GND)Schottky-Diode / Galliumnitrid / Schottky-Kontakt / Transporteigenschaft
URNurn:nbn:at:at-ubl:1-22793 Persistent Identifier (URN)
 Das Werk ist gemäß den "Hinweisen für BenützerInnen" verfügbar
GaN-based Schottky diodes: a study of ideality factor and barrier height [7.86 mb]
Zusammenfassung (Englisch)

Devices and structures based on GaN have a wide range of applications, including opti- cal devices, ultraviolet Schottky barrier photodiodes, solar-blind Schottky photodiodes, metal-semiconductor field effect transistors and high mobility transistors. One of the still open challenges is to obtain metal-semiconductor Schottky contacts not only with a high barrier height but also with a low leakage current. Studies on the temperature dependence of the current-voltage (I-V) characteristics to determine the transport processes in this type of material have revealed that threading dislocations are of fundamental importance to explain the behavior of the ideality factor and the height of the Schottky barrier. Generally speaking is it of peculiar interest to under- stand the different conduction mechanisms to enhance the quality of devices made of gallium nitride, e.g. Schottky diodes. In this thesis, the fabrication, characterization and further processing of GaN sam- ples with Ni or Pt contacts are reported and not only the barrier height but also the ideality factor of the probes is measured for temperatures ranging from 1,8 K to room temperature. The ideality factor accounts for the non-ideal diode behavior of the contact. For the samples under consideration we have values > 2 for the ideality factor, which means, that the samples do not follow the theoretically predicted behavior. As the results are not in accordance to what is expected theoretically, dislocation-assisted tunnelling of carriers across the Schottky barrier has to be considered. The charged dislocations open up a new path for the carriers from the layer-substrate interface to the sample surface. This an be confirmed by I-V measurements and the determination of the characteristic tunneling energy. The present model can be applied to explain the transport mechanism where the transport characteristics are severely affected by a degenerate GaN-sapphire interface and dislocations reaching from this interf

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