Abstract: Hetero-epitaxy by chemical vapor deposition （CVD） is an alternative for silicon on insulator （SOI） material fabrication. The fabrication of Si-based double hetero-epitaxial SOI materials Si/γ-Al₂O₃/Si was reported. First, single crystalline γ-Al₂O₃ （100） insulator films were grown epitaxially on Si（100） by LPCVD, and then Si（100） epitaxial films were grown on γ-Al₂O₃ （100）/ Si（100） epi-substrates using a CVD method similar to silicon on sapphire （SOS） epitaxial growth. The Si/γ-Al₂O₃ （100）/ Si（100） SOI materials were characterized in detail by RHEED, XRD, AES and MIS electric measurement techniques. The results demonstrate that the device-quality novel SOI materials Si/ γ-Al₂O₃ （100）/ Si（100） are fabricated successfully. Both γ-Al₂O₃ and Si films are single crystalline. γ-Al₂O₃ film exhibits a good insulating property. Two hetero interfaces of SOI structure are basically abrupt. The novel double heteroepitaxial SOI materials can be applied for fabrication of CMOS device and circuits.