A semiconductor substrate including a first epitaxial semiconductor layer is provided. The first epitaxial semiconductor layer includes a first semiconductor material, and can be formed on an underlying epitaxial substrate layer, or can be the entirety of the semiconductor substrate. A second epitaxial semiconductor layer including a second semiconductor material is epitaxially formed upon the first epitaxial semiconductor layer. Semiconductor fins including portions of the second single crystalline semiconductor material are formed by patterning the second epitaxial semiconductor layer employing the first epitaxial semiconductor layer as an etch stop layer. At least an upper portion of the first epitaxial semiconductor layer is oxidized to provide a localized oxide layer that electrically isolates the semiconductor fins. The first semiconductor material can be selected from materials more easily oxidized relative to the second semiconductor material to provide a uniform height for the semiconductor fins after formation of the localized oxide layer.