Growth of High-Electron-Mobility InN by RF Molecular Beam Epitaxy

Abstract

We succeeded in growing InN films two-dimensionally by radio-frequency plasma-excited molecular beam epitaxy (RF-MBE), using a low-temperature-grown InN buffer layer. From the results of reflection high-energy electron diffraction (RHEED) observation and X-ray diffraction (XRD) measurement, it was found that a single crystal of InN films with a wurtzite structure was obtained. Moreover, from the results of Hall effect measurement, it was found that the InN films had quite high electron mobilities. The best electron mobility at room temperature obtained in this study was 760 cm2/V·s and the corresponding carrier density was 3.0×1019 cm-3. To our knowledge, this electron mobility is the highest value ever reported for single crystal InN films.

RF-Molecular Beam Epitaxy Growth and Properties of InN and Related Alloys

“…9. 20) A high density of In droplets is observed for the sample grown under an RF-plasma power of 230 W, apparently due to a lack of an active nitrogen source. The pit size of the InN grown at 240 W is much smaller than that of the 250-W sample.…”

“…17) Improvements in crystal quality were realized by various techniques such as insertion of low-temperature GaN, 18) AlN, 19) and InN 20) buffer layers. Within a relatively short period of time, MBE growth studies produced high-quality films with residual electron concentrations of 1:6 Â 10 18 cm À3 and a room temperature mobility of 1180 cm 2 / Vs. 18) Such rapid progress is probably due to the inherent advantage of the MBE growth method.…”

Influence of V/III molar ratio on the formation of In vacancies in InN grown by metal-organic vapor-phase epitaxy

“…3 The growth of high quality InN is rather difficult. Bulk material is not available but high quality films on sapphire have been fabricated by molecular beam epitaxy 5,6 ͑MBE͒ and also by metal-organic vapor-phase epitaxy ͑MOVPE͒.…”

In-polar InN grown by plasma-assisted molecular beam epitaxy

“…Reports of using an AlN buffer layer on sapphire, 12 a lowtemperature InN buffer layer on sapphire, 13 Initial In-polar InN epilayers were grown directly on the GaN templates. This resulted in InN layers that were not fully coalesced and exhibited many surface pits as observed by AFM; therefore, it was necessary to optimize the buffer layer to precede InN growth.…”