Interfacial reaction control and its mechanism of AlN epitaxial films grown on Si(111) substrates by pulsed laser deposition

Abstract

High-quality AlN epitaxial films have been grown on Si substrates by pulsed laser deposition (PLD) by effective control of the interfacial reactions between AlN films and Si substrates. The surface morphology, crystalline quality and interfacial property of as-grown AlN/Si hetero-interfaces obtained by PLD have been systemically studied. It is found that the amorphous SiAlN interfacial layer is formed during high temperature growth, which is ascribed to the serious interfacial reactions between Si atoms diffused from the substrates and the AlN plasmas produced by the pulsed laser when ablating the AlN target during the high temperature growth. On the contrary, abrupt and sharp AlN/Si hetero-interfaces can be achieved by effectively controlling the interfacial reactions at suitable growth temperature. The mechanisms for the evolution of interfacial layer from the amorphous SiAlN layer to the abrupt and sharp AlN/Si hetero-interfaces by PLD are hence proposed. This work of obtaining the abrupt interfaces and the flat surfaces for AlN films grown by PLD is of paramount importance for the application of high-quality AlN-based devices on Si substrates.

Microstructures and growth mechanisms of GaN films epitaxially grown on AlN/Si hetero-structures by pulsed laser deposition at different temperatures

“…In this work, we report on the epitaxial growth of GaN films with homogeneous thickness distribution on the homogeneous AlN/Si hetero-structures that were achieved in our previous work by PLD with optimized laser rastering program 28 29 . On the one hand, the programmed and optimized movement of the rastering mirror intentionally changes the incident angles of precursors toward the substrates produced by the each laser pulse, resulting in a statistically homogeneous distribution of precursors on the substrate and thereby the homogeneous thickness of as-grown GaN films can be achieved 26 27 28 29 . On the other hand, the surface morphology, crystalline quality, and interfacial property of as-grown ~300 nm-thick GaN films with the growth temperature ranging from 550 to 850 °C are studied systematically.…”

“…It is known that the white-light interferometry requires that the thickness of as-grown films should usually be >200 nm 28 29 . Therefore, the thickness of as-grown AlN films obtained in this work is calculated by grazing incident X-ray reflectivity measurement reported in our previous work 28 .…”

Structural Characterization of Al0.37In0.63N/AlN/p-Si (111) Heterojunctions Grown by RF Sputtering for Solar Cell Applications

“…Therefore, it is likely that the AlN buffer traps the oxygen through the formation of Al-O bonds, thus hindering its diffusion into the AlInN growing layer, which is also the case for the AlInN layers deposited directly on Si (111). The O contamination may have come from the Si surface before growing, as due to the system limitations, it was degassed at a temperature below that required to remove the native oxide [27]. The structural characterization carried out through HRTEM analyses reveal the epitaxial relationship, which is understood as the alignment between the main planes and directions of the growing AlInN and the silicon substrate, in both cases (with and without the buffer layer).…”

“…Therefore, it is likely that the AlN buffer traps the oxygen through the formation of Al-O bonds, thus hindering its diffusion into the AlInN growing layer, which is also the case for the AlInN layers deposited directly on Si (111). The O contamination may have come from the Si surface before growing, as due to the system limitations, it was degassed at a temperature below that required to remove the native oxide [ 27 ].…”

Second Harmonic Generation Response in Thermally reconstructed Multiferroic β′- Gd2(MoO4)3 Thin Films

“…Thin films prepared by PLD are typically homogenous, without cracks or discontinuities and highly tunable, due to the several parameters involved in the deposition process 52 . Moreover, PLD is a technique known to favor the formation of stoichiometric films 52 , 53 and it is regularly used in the investigation of multifunctional 54 , 55 and epitaxial 9 , 15 , 56 – 58 thin films and nanomaterials. Reasons for which PLD is an ideal candidate for the investigation of GMO thin films.…”