US Patent 7160751 Method of making a SOI silicon structure

A process for making a microelectromechanical device having a moveable component defined by a gap pattern in a semiconductor layer of a silicon-on-insulator wafer involves the use of a plurality of deep reactive ion etching steps at various etch depths that are used to allow a buried oxide layer of the silicon-on-insulator wafer to be exposed in selected areas before the entire moveable component of the resulting device is freed for movement. This method allows wet release techniques to be used to remove the buried oxide layer without developing stiction problems. This is achieved by utilizing deep reactive ion etching to free the moveable component after a selected portion of the buried oxide layer has been removed by wet etching.