Molecular beam epitaxy (MBE) is widely recognized as the primary technique for achieving layer-by-layer, defect-free growth of semiconductor epitaxial layers under ultra-high vacuum (UHV) conditions, typically at base pressures around 10-10-10-11 mbar. However, its application to halide perovskites has been limited despite the potential for exceptional control over film composition, thickness, and crystallinity at the atomic level. In the rapidly advancing field of halide perovskites, employing MBE offers unique advantages essential for fully harnessing the optoelectronic properties of these materials for electronic and photovoltaic applications. In this talk, we will describe the advances performed in the development of MBE growth of halide perovskite, discussing the epitaxial growth mechanisms, structural characteristics, and surface morphology of CsPbBr₃ films on various technologically relevant substrates, including Si(111), Si(001), Ag(111), and particularly SiO₂-buffered Si(111). We highlight the critical role of an ultra-thin amorphous SiO₂ interlayer, introduced by exposure of a clean Si(111)7×7 surface to molecular oxygen, which significantly enhances film quality by mitigating lattice mismatches and facilitating epitaxial growth through a novel "slip-and-stick" mechanism. [1,2] This buffer layer effectively decouples the CsPbBr₃ film from the reactive silicon surface, preventing molecular dissociation and facilitating the formation of highly crystalline films. The grown CsPbBr₃ perovskite layers were extensively characterized using multiple techniques, including in-situ Auger electron spectroscopy, XRD, RHEED and HAADF-STEM. These analyses revealed uniform stoichiometry throughout the grown films and exceptional crystal quality, with XRD patterns demonstrating sharp reflections indicative of a pure orthorhombic phase with full widths at half maximum (FWHM) as low as 0.035°, comparable to single-crystal silicon standards. Such unprecedented crystallinity points to a significantly reduced defect density and negligible residual stress. HAADF-STEM investigations confirmed the presence of large epitaxial domains spanning several micrometers, each exhibiting uniform alignment of the c-axis perpendicular to the substrate. These insights underline the potential of CsPbBr₃ perovskite thin films in tandem photovoltaic architecture, especially when integrated onto silicon platforms, promising substantial improvements in device efficiency and stability. The thin amorphous SiO2 interlayer, approximately 2 nm thick, was pivotal in promoting this highly ordered growth mode, as demonstrated through comprehensive structural modeling and DFT simulations.[2] Computational analyses corroborated experimental observations, indicating the "slip-and-stick" diffusion mechanism where CsPbBr₃ molecules traverse amorphous silica surfaces without significant energy barriers, preserving molecular integrity and enabling homogeneous layer-by-layer film deposition. The successful epitaxial growth of CsPbBr₃ perovskite films using MBE, complemented by a silica buffer layer, highlights the critical interplay of substrate engineering and controlled deposition processes in developing high-quality perovskite materials. We will also briefly discuss the MBE growth of other halide perovskites with lower bandgaps. These findings provide a significant step forward toward the integration of fully inorganic perovskites into robust, efficient optoelectronic devices, next-generation tandem solar cells as well as advanced electronic devices.