We have successfully formed and separated a very thin silicon-dioxide (SiO2) film with a thickness of approx. 1 nm. The thin SiO2 film was chemically grown on Si using a wet chemical treatment which is commonly used in semiconductor manufacturing. Highly selective etching of the underlying Si, through the native oxide, can be achieved using chlorine (Cl-2) gas. Such a unique phenomenon allows the formation and separation of native oxide from the Si surface. The native oxide film, which is suspended at its edges by thick-SiO2, remains at the original level of the Si surface even after etching. The suspended Si-native oxide membrane is imaged using scanning electron microscopy (SEM). It is presumably the thinnest separated film ever recorded. The similar to 1-nm-thickness SiO2 membrane suspended by thick-SiO2 can support subsequent film deposition. The sequential processes of native oxide formation on patterned Si. etching the Si by Cl-2 through the native oxide. and film deposition onto the native oxide membrane, can make a cavity in the solid-state substrate. This novel technique of creating a cavity by using a membrane of Si-native oxide can be applied to fabricate 3D micro-systems like pipes, diaphragms, tubes, and wave-guides on the solid-state circuits. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.