A process for fabricating a suspended microelectromechanical system (MEMS) structure comprising epitaxial semiconductor functional layers that are partially or completely suspended over a substrate. A sacrificial release layer and a functional device layer are formed on a substrate. The functional device layer is etched to form windows in the functional device layer defining an outline of a suspended MEMS device to be formed from the functional device layer. The sacrificial release layer is then etched with a selective release etchant to remove the sacrificial release layer underneath the functional layer in the area defined by the windows to form the suspended MEMS structure.