Improvement of Crystal Quality of RF-Plasma-Assisted Molecular Beam Epitaxy Grown Ga-Polarity GaN by High-Temperature Grown AlN Multiple Intermediate Layers

Abstract

The effects of high-temperature-grown AlN multiple intermediate layers (HT-AlN-MILs) on the crystal quality of Ga-polarity GaN layers grown on (0001) Al 2 O 3 substrates by molecular beam epitaxy using rf-plasma nitrogen source were investigated. The high-temperature-grown AlN intermediate layers (HT-AlN-ILs) with different thicknesses were found to play different roles in the improvement of crystal quality. The 8-nm-thick HT-AlN-ILs brought about improvement of electrical properties. On the other hand, the 2-nm-thick HT-AlN-ILs improved the surface morphology. The combination of these 8-nm-HT-AlN-ILs and 2-nm-HT-AlN-ILs improved both the electrical properties and the surface morphology concurrently.

Subtle interplay between polytypism and preferred growth direction alignment in GaN nanorods non-catalytically grown on Si(111) substrates by using hydride vapor phase epitaxy

“…As a consequence, the performance of heteroepitaxial-GaN-film-based devices is deteriorated to some extent by extended defects. To solve this inherent problem of high density dislocation in heteroepitaxially-grown-GaN-film-based devices, many approaches such as epitaxial lateral overgrowth [4], multiple intermediate layers [5], liquid phase epitaxy [6,7] have been proposed. Due to complicate processes and insufficient reduction of dislocation density in these approaches, alternative methods have been, however, constantly pursued.…”

Growth and characterization of InGaN/GaN nanocolumn LED

“…The threading dislocations reduce the emission efficiency, increase the leakage current, and shorten the life time of devices. Many dislocation reduction techniques such as lateral overgrowth 1 , low-temperature buffer layer 2 , multiple intermediate layer 3 , and so on have been developed. Although using these techniques, it is difficult to reduce the dislocation density to be less than 10 6 cm -2 .…”

Selective growth of N-polar InN through an in situ AlN mask on a sapphire substrate

“…4,6,15,25,31,32 On the other hand, high temperature (HT) AlN layers grown on sapphire substrates usually possess Al-polarity and have been widely used to control the polarity of the following layers to be metal-polar. [32][33][34] Consequently, InN on top of AlN/sapphire should be In-polar. If the AlN layer is thin enough and only partially covers the sapphire surface, it can be employed as an in situ metal polar mask.…”