Microelectromechanical systems (MEMS) and methods

The present disclosure relates to a method of fabricating a reflector, the reflector being at least partially reflective and at least partially transmissive for at least a wavelength of electromagnetic radiation; the method comprising: forming a first material layer defining a bottom layer; forming a sacrificial layer on the bottom layer; forming a second material layer defining a top layer on the sacrificial layer and a supporting structure connected to the bottom layer; and removing at least part of the sacrificial layer to form a cavity between the bottom layer and the top layer such that the supporting structure supports the top layer relative to the bottom layer and no further supporting structure is provided within the cavity, wherein after the at least part of the sacrificial layer is removed, at least the top layer has residual tensile stress.