Scientific highlights
J. Kuzmik et al.
08 Jun 2017

Current conduction mechanism and electrical break-down in InN grown on GaN

Current conduction mechanisms, including electron mobility, drift velocity and electrical break-down have been investigated in MBE-grown InN layers at the Foundation for Research and Technology Hellas.
View of the InN resistor after applying destructive electric pulse.

HERAKLION, GREECE- BRATISLAVA, SLOVAKIA.Future ultra-high-frequency transistors may be designed with InN channel material. In fact, this approach may lead to the fastest solid-state transistors ever due to the extremely high theoretical electron velocity of InN. However, electron velocity in InN channel transistors has never been measured.

(GaN)/InN samples were grown in a Molecular-Beam Epitaxy (MBE) system equipped with nitrogen RF plasma source. A careful preparation of the growth chamber/vacuum and the source materials was employed to limit the incorporation of unintentional donor impurities, such as oxygen atoms, in the InN layers. GaN buffer was MBE grown on a commercially available high-resistivity GaN-on-sapphire template, followed by an InN film. An optimized InN growth process was carried out, according to the results of our previous InN MBE investigations.

the study confirmed feasibility of InN channel transistors, reaching electron velocity far above conventional GaN

The InN films were initially characterized by conductivity and Hall Effect measurements ranging from room temperature (RT) down to 20 K, by high-resolution X-ray diffraction (HRXRD), and by photoluminescence (PL).

Special test structures have been used to characterize InN resistors using current-voltage short pulses. Premature breakdown has appeared before reaching current/velocity saturation, which was linked to defects in InN due to heteroepitaxial growth and strain relaxation. As pointed by Georgakilas, InN growth needs further advancement. Nevertheless as said by Kuzmik, our study confirmed feasibility of InN channel transistors, reaching electron velocity far above conventional GaN.

Publication Details

Applied Phys. Lett. 110 (2017) 232103

Current conduction mechanism and electrical break-down in InN grown on GaN

J. Kuzmik, C. Fleury, A. Adikimenakis, D. Gregušová, M. Ťapajna, E. Dobročka, Š. Haščík, M. Kučera, R. Kúdela, M. Androulidaki, D. Pogany, and A. Georgakilas


NFFA-Europe Facilities and Techniques

The Institute of Electronic Structure and Laser (IESL) of the Foundation for Research and Technology Hellas has a unique complete III-V microelectronics facility in Greece jointly with the Physics Department of University of Crete.

Facilities, directly related to this project, include: (1) an MBE growth laboratory installed in a class-1000 clean room, having a RIBER 32P MBE system with nitrogen RF-plasma source for growth of III-Nitrides, (2) a complete device fabrication laboratory installed in a class-1000 clean room, with deep-UV mask aligner with backside alignment capability, e-beam evaporator, RF and DC sputtering, RIE and PECVD systems and (3) a full line of optical, electrical and structural material and device characterization techniques, such as 14-300K PL, micro-PL, PR, ER, C-V, DLTS, quasistatic I-V, RF S-parameter, noise and power measurements up to 20 GHz, on-wafer RF probes, AFM, SEM, Nomarski, HRXRD.

About the authors
Dr. Ján Kuzmík is a senior researcher at the Institute of Electrical Engineering, Slovak Academy of Sciences and a Head of the Department of III-V semiconductors. He received his PhD degree from Slovak Academy of Sciences in 1991. From 1991-1994 he was a research fellow at IESL FORTH Crete, Greece, involved in the ESPRIT project on technology of III-V microwave circuits and Brite Euram project on SiC devices. He was a JSPS fellow at the Kyoto Institute of Technology, Japan (SiC technology) in the period of 1996-1998. Since 2002 till 2011 he had been with the Institute for Solid State Electronics at the Technical University Vienna where he worked in the fields of electro-optical characterization and thermal effects in GaN HEMTs, III-V device physics, processing and characterization. In 2012 he was an invited professor at the University of Hokkaido, Japan.
Alexandros Georgakilas is a professor in the Physics Department of University of Crete and a collaborating researcher of IESL-FORTH. His current research is focused on the development by Molecular Beam Epitaxy of III-nitride heterostructure and nanowire materials enabling advanced sensors, electronic and optoelectronic devices.
For more info

Jan Kuzmik  
Institute of Electrical Engineering - Slovak Academy of Sciences
Dubravska cesta 9
841 04 Bratislava