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Epitaxy
Published in Kumar Shubham, Ankaj Gupta, Integrated Circuit Fabrication, 2021
Molecular Beam Epitaxial growth technique has a number of advantages over other techniques. A particular advantage is that it permits growth of crystalline layers at temperatures where solid-state diffusion is negligible. Since chemical decomposition is not required for growth, deposition species need require only enough energy to migrate along the substrate surface to crystalline bonding site. The impurity dopant incorporation during molecular beam epitaxial growth is possible by having an additional source of the dopant. As a result, MBE has rapidly established itself as a versatile technique for growing elemental and compound semiconductor films. Thus using MBE, it is possible to produce multilayered structures including superlattices with layer thickness as low as 10 Å for DH lasers and waveguide applications.
Introduction
Published in Kwang Leong Choy, Chemical Vapour Deposition (CVD), 2019
The MBE growth process occurs on the substrate crystal surface, which plays a crucial role as it influences directly the arrangement of the atomic species of the growing film. Many studies have been performed on the interaction of substrates and growing films in order to understand the growth process. It is considered that the construction of the surface phase diagram of GaAs, by observing the As-stabilized and Ga-stabilized surface structures with high-energy electron diffraction (HEED), was the beginning of controlled epitaxial growth of GaAs thin film as shown in Figure 1.42, but the understanding of reconstruction of surface structures in MBE was not well accepted by the surface physics community in the early days, and is now well established [70]. Moreover, there is migration rate difference between adatoms (like Ga, In) on different facets to form ‘kinks’ in the channel and, as shown in Figure 1.43, the film in the ridge and groove is 25%–50% thicker than that on the side wall. This makes MBE on nonplanar substrate potentially useful for optoelectronic devices [75b].
Introduction
Published in Kwang Leong Choy, Chemical Vapour Deposition (CVD), 2019
The MBE growth process occurs on the substrate crystal surface, which plays a crucial role as it influences directly the arrangement of the atomic species of the growing film. Many studies have been performed on the interaction of substrates and growing films in order to understand the growth process. It is considered that the construction of the surface phase diagram of GaAs, by observing the As-stabilized and Ga-stabilized surface structures with high-energy electron diffraction (HEED), was the beginning of controlled epitaxial growth of GaAs thin film as shown in Figure 1.42, but the understanding of reconstruction of surface structures in MBE was not well accepted by the surface physics community in the early days, and is now well established [70]. Moreover, there is migration rate difference between adatoms (like Ga, In) on different facets to form ‘kinks’ in the channel and, as shown in Figure 1.43, the film in the ridge and groove is 25%–50% thicker than that on the side wall. This makes MBE on nonplanar substrate potentially useful for optoelectronic devices [75b].
A critical overview of thin films coating technologies for energy applications
Published in Cogent Engineering, 2023
Mohammad Istiaque Hossain, Said Mansour
The article has been arranged in a way to provide an in-depth knowledge to the wide range of readers where both theoretical and basic mechanism of PVD methods are considered. Such techniques are the best due to the technological adaptability to fabricate inorganic, hybrid, and nanocomposite thin films. MBE is a significant deposition technique to grow epitaxial, layered structures under ultrahigh vacuum conditions on different substrate materials (Kim et al., 2022; Richards et al., 2022; Yao et al., 2022; Zhao et al., 2022; Zhu et al., 2022). In general, chemical reaction occurs through molecular beam impinging on the surface, where this chemical reaction is the material transition from the gas phase in the molecular beam to the solid state on top of the substrate. MBE tool allows higher qualities of the deposited films through heating and rotation capabilities. In-situ reflection high energy electron diffraction (RHEED) can be used to check the quality of the deposited films, which is an added advantage. In this tool, growth process involves controlling molecular and/or atomic beams via shutters and source temperature, deposited on mono-crystal substrate for epitaxial growth.