In situ transmission electron microscopy of AlN growth by nitridation of (0001) α-Al2O3

Abstract

Articles you may be interested inMorphology and microstructure evolution of Al x Ga 1 − x N epilayers grown on GaN/sapphire templates with AlN interlayers observed by transmission electron microscopy

X-ray photoelectron spectroscopic study on sapphire nitridation for GaN growth by hydride vapor phase epitaxy: Nitridation mechanism

“…With the rf nitrogen plasma source, the formation of protrusions also depends on nitridation temperature. In contrast, negligible change in the sapphire surface roughness was observed in nitridation studies in MBE, using a NH 3 source 14 and an ECR nitrogen plasma, for process times up to 180 min. 15 The state of the pregrowth surface, after the nitridation of sapphire in the HVPE growth system, can be expected to be different from what has been observed in nitridation studies using other growth techniques.…”

“…The normalized concentration of N 1s and O 1s was calculated from the XPS peak area divided by the corresponding atomic sensitivity factor ͑ASF͒ and normalized with the Al 2p peak area. The Al 2p peak was commonly used as a reference in sapphire nitridation studies 4,[11][12][13][14][15][16][17][18][19] since the vapor pressure of aluminum containing species ͑e.g., AlO, Al 2 O, and Al͒ is negligible at 1100°C. 24 The concentration of surface aluminum atoms was assumed therefore to be approximately constant before and after nitridation.…”

“…30,31 The Al 2p peak is commonly used as reference for other elemental peaks in previous nitridation studies. 4,[11][12][13][14][15][16][17][18][19] The Al 2p peak serves as a reference since the vapor pressure of aluminum containing species, e.g., AlO, Al 2 O, and Al, is negligible at 1100°C. Thus, the concentration or total amount of surface aluminum atoms were considered constant before and after nitridation.…”

“…8,9 Studies on sapphire nitridation in a MBE system using a rf nitrogen plasma suggested the formation of AlN and NO molecules on the sapphire, 3,23 as well as an AlN x O 1Ϫx intermediate compound. 4 In some cases, a crystalline AlN layer was reportedly formed during sapphire nitridation in MBE using NH 3 , 13,14 an ECR nitrogen plasma, 15,16 and a helicon-wave nitrogen plasma. 17 Using a constricted nitrogen plasma, it was demonstrated that both AlN and AlN x O 1Ϫx compounds were formed during sapphire nitridation.…”

Influence of Active Nitrogen Species on the Nitridation Rate of Sapphire

“…All of the nitridations performed with the Oxford source gave similar results, but with different time scales for differing conditions. Yeadon et al have shown [8] that AlN and Al 2 O 3 are immiscible and nitridation proceeds by the formation of an AlN overlayer on the Al 2 O 3 . Atomic force microscopy of a sapphire surface nitrided under similar conditions to that of the sample of Fig.…”