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.

Current-voltage characteristics of InN resistors