Effect of Growth Temperature on Formation of Amorphous Nitride Interlayer between AlN and Si(111)

Abstract

The formation of an amorphous interlayer between AlN and Si(111), which may degrade the film quality, is studied by varying the substrate temperature from 860 to 1010 °C in metal–organic chemical vapor deposition with a preflow of trimethylaluminum. The microstructure and chemistry of the amorphous interlayer have been investigated using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Cross-sectional TEM examinations show that AlN is directly in contact with Si for growth at 860 °C. At higher growth temperatures, an amorphous interlayer can be formed even if an AlN layer has been previously deposited on Si, and its thickness increases with growth temperature. The XPS depth profile across the amorphous interlayer formed at 1010 °C shows that both Al and N exhibit similar distribution, which gradually decreases toward the Si substrate whereas the Si concentration has the opposite distribution. The composition of the amorphous interlayer is determined to consist of Al, Si, and N.

Temperature effect on Al predose and AlN nucleation affecting the buffer layer performance for the GaN-on-Si based high-voltage devices

“…The amorphous interlayer on the HT-3 sample seems to be continuous without any direct contact points between AlN and Si, therefore we conclude that it is likely formed later on during the 200 nm thick AlN layer growth, similar to Ref. 26.…”

“…The 5:4 lattice matching between 1100 AlN { ¯} and 111 Si { } planes was observed. 24,26,27,53,54) We have found the same AlN/Si lattice matching on both samples. The amorphous interlayer on the HT-3 sample seems to be continuous without any direct contact points between AlN and Si, therefore we conclude that it is likely formed later on during the 200 nm thick AlN layer growth, similar to Ref.…”

“…An amorphous layer can be then formed by the AlSiN disordered alloy. 26) Another explanation is that the Si x N y is always formed unintentionally on the Si substrate at HTs prior to the growth due to ammonia-containing residues and deposits in the MOCVD reactors. Good AlN quality despite the Si x N y presence could then be explained by local contacts between the Si substrate and the AlN nucleation layer through the discontinuous Si x N y .…”

(Invited) Epitaxial III-Nitride Film Growth in a Single Wafer Rotating Disk MOCVD Reactor

“…However, an amorphous thin layer of SiN x can still exist at the Si-AlN interface due to the reaction between N and the Si substrate (31)(32)(33)(34). The conditions for TMAl preflow (such as time, TMAl flow, and temperature) (34)(35)(36)(37) are critical in affecting the Si-AlN interface, which can determine the structural quality, surface morphology, and surface pits in the AlN layer and the subsequently grown GaN layers.…”

Structural properties of Al-rich AlInN grown on c-plane GaN substrate by metal-organic chemical vapor deposition

“…A 1.5-μm-thick homoepitaxial GaN film was firstly grown on GaN substrate at 970°C by MOCVD (Veeco Emcore D-180; Veeco Instruments Inc., Plainview, NY, USA) using TMGa and NH 3 as the precursors for Ga and N to improve GaN crystallinity. After the growth of GaN layer, TMAl and NH 3 were flowed into the chamber at 990°C for 1 min [ 24 ], followed by further growth of AlInN epilayer at temperature of 780 and 800°C. A TMAl/TMIn ratio of 1/10, a reactor pressure of 100 Torr, and a NH 3 flow rate of 15,000 sccm were used for all AlInN growth.…”