Structural investigation of nitrided c-sapphire substrate by grazing incidence x-ray diffraction and transmission electron microscopy

Abstract

A grazing incidence x-ray diffraction with a synchrotron radiation and a cross-sectional high-resolution transmission electron microscopy were performed on the sapphire surface nitrided at 1080°C for 30min. The thickness of the nitrided layer was about 2nm. It was found out that the wurtzite, zinc-blende, and 30° rotated zinc-blende aluminum nitrides were formed on the sapphire surface. The 30° rotated zb-AlN formed the incoherent interface and has higher activation energy of formation, while the nonrotated zb-AlN formed the coherent interface.

Hydride vapor phase epitaxy of GaN on the vicinal c-sapphire with a CrN interlayer

“…AlN), respectively. The crystallographic relationship between w-AlN and sapphire agreed well with the previous result [8,9]. Here, it can be surmised that the AlN layer between sapphire and CrN may be influenced by its lower sapphire substrate.…”

Nitridation of Sapphire as a Precursor to GaN Growth: Structure and Chemistry

“…Our diffraction evidence however appears quite unambiguous, and in addition we detect the two twin related variants that can only form out of the observed crystallographic relationship between the cubic rs-AlN nitride layer and sapphire (our Figures and ). Finally, it is noted that Lee at al . used grazing incidence X-ray diffraction to identify mixtures of wz-AlN and zb-AlN after nitridation at 1080 °C for 30 min, while Mohn et al used high resolution TEM and HADDF images to propose duplex layers of wz-AlN and rhombohedral AlON structure after nitridation at 1080 °C for 7 min.…”

“…Finally, it is noted that Lee at al. 17 The relationship between the structures of the nitrided layers obtained in this study and the sapphire substrate are shown in Figure 10. The approximate thickness of the nitrided layer, as experimentally observed, is indicated by the dashed lines and is a fraction of the sapphire unit cell.…”

“…An amorphous Al x O y N z layer has been suggested by Uchida et al, while Vennéguès et al proposed that the nitride phase has a hexagonal wurtzite AlN structure (wz-AlN). Rouvière et al identified a cubic Al–O–N phase, while Lee et al suggested a complex of wz-AlN and zincblende-AlN (zb-AlN) phases in the nitrided layer. More recently, the wz-AlN phase has been identified in the nitrided layer by Milakhin et al using the reflection high energy electron diffraction technique (RHEED).…”

Formation of m-plane AlN on plasma-nitrided m-plane sapphire

“…For the growth of high-quality III-nitrides on sapphire substrates, the nitridation of sapphire may be necessary prior to deposition. [1][2][3][4][5][6][7][8][9][10][11][12][13] Thermal nitridation at a high temperature with N 2 and NH 3 is often used in metalorganic chemical vapor deposition. [1][2][3]13,14) Plasma nitridation with a radio frequency (RF) source and electron-cyclotron-resonance plasma has been performed in the past as well.…”