1：Experimental Design and Method Selection:

The study employed solid state dewetting of Al thin films on sapphire, followed by Au deposition and annealing in different atmospheres to investigate pore formation and intermetallic phase growth. A kinetic model was developed to describe oxygen diffusion and Al oxidation.

2：Sample Selection and Data Sources:

C-plane oriented sapphire wafers with a miscut of 0.2° toward the m-plane were used. Thin Al and Au films were deposited via molecular beam epitaxy (MBE).

3：2° toward the m-plane were used. Thin Al and Au films were deposited via molecular beam epitaxy (MBE). List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: MBE tool for deposition and annealing, rapid thermal annealing furnace (ULVAC-RIKO MILA 5000 P-N), X-ray diffractometer (Rigaku SmartLab), high-resolution scanning electron microscope (Zeiss Ultra-Plus), focused ion beam system (FEI Helios NanoLab DualBeam G3 UC), transmission electron microscopes (FEI Titan 80-300 KeV S/TEM and FEI Themis G2 300 80-300 keV S/TEM), energy dispersive X-ray spectroscopy (EDS), electron backscattered diffraction (EBSD), and electron energy loss spectroscopy (EELS). Materials included Al and Au thin films, sapphire substrates, and gases (air, vacuum, forming gas).

4：Experimental Procedures and Operational Workflow:

A 10 nm Al film was deposited on sapphire and annealed at 600°C for 18 hours in MBE. A 20 nm Au film was then deposited. Subsequent annealing was performed at 170°C for 30 or 60 minutes in air, vacuum, or forming gas. Characterization involved XRD, HRSEM, FIB for cross-sections, TEM, EDS, EBSD, and EELS.

5：Data Analysis Methods:

XRD spectra were fitted with Gaussians for phase identification. EDS provided elemental maps and composition profiles. EBSD was used for grain size analysis. A kinetic model based on diffusion equations was developed and solved numerically.