A method of growing III-N material on a silicon substrate including the steps of epitaxially growing a buffer layer of REO material on a silicon substrate, epitaxially growing a layer of REN material on the surface of the buffer, and epitaxially growing a thin protective layer of REO on the surface of the REN material layer. The substrate and structure can then be conveniently transferred to another growth machine in which are performed the steps of transforming or modifying in-situ the REO protective layer to a REN layer with a nitrogen treatment and epitaxially growing a layer of III-N material on the modified protective layer.