CC BY 4.0Supik, Ella SusannElla SusannSupikSchreiber, WaldemarWaldemarSchreiberWagenfeldt, AndyAndyWagenfeldtCho, JinyounJinyounChoDessein, KristofKristofDesseinMamiyev, Zamin Q.Zamin Q.MamiyevTegenkamp, ChristophChristophTegenkampWeiss, CharlotteCharlotteWeissBett, Andreas W.Andreas W.Bett2025-10-132025-10-132025https://publica.fraunhofer.de/handle/publica/497289https://doi.org/10.24406/publica-573410.1149/2162-8777/ae08e410.24406/publica-57342-s2.0-105017505011To meet the rising demand for germanium, a critical raw material commonly used as substrates for highly efficient III−V solar cells, innovative, sustainable and cost-effective substrate alternatives, such as engineered germanium substrates and germanium on silicon virtual substrates, are currently under development. In this study, we developed a high throughput homoepitaxial germanium deposition process that can be applied to both substrate alternatives. We successfully deposited 10 μm thick, high-quality germanium epilayers at an elevated growth rate and high molar yield without compromising quality utilizing a batch-type atmospheric pressure chemical vapor deposition (APCVD) reactor in a GeCl<inf>4</inf>-H<inf>2</inf> system. Under optimal deposition conditions at 750 °C with a GeCl<inf>4</inf>/H<inf>2</inf> ratio of 1.11 × 10⁻², we achieved a significant growth rate of 0.37 μm min⁻¹ and a molar yield of 36%. Characterization of the crystalline structure and surface morphology confirmed that the epilayers exhibit high crystalline quality, comparable to bulk Czochralski wafers, affirming their suitability as substrates for highly efficient III−V solar cells.entrueAPCVDChemical Vapor DepositionEpitaxyGermaniumGermanium tetrachlorideThin Film Epitaxyjournal article