Abstract: The invention provides a method of forming a sealed diaphragm (3) on a substrate (1) which comprises providing on the substrate (1) a sacrificial layer (2) , providing a diaphragm layer (3) over the sacrificial layer (2), providing at least one aperture (5) in the diaphragm layer (3) which is spaced from the periphery of the diaphragm layer (3), at least partially removing the sacrificial layer (2) from between the substrate (1) and the diaphragm layer (3) by way of the at least one aperture (5) and closing the at least one aperture (5).

Abstract: A method of producing filaments of sub-micron cross-sectional dimensions including the steps of obtaining a substrate having a base and a delineating layer on the base and a step in a surface of the delineating layer, providing a layer of a material from which the filament is to be formed on the surface which replicates the step in the surface, anisotropically etching the layer of filament material in the direction of the surface so as to leave a filament of the material adjacent the step, and removing the delineating layer to wholly or partially separate the filament from the substrate.

Abstract: The invention provides a method of producing on a substrate a diaphragm which is electrically isolated from the substrate. The method comprises obtaining a substrate (2) having a diaphragm(1) thereon which comprises a flexible central portion (1a) and a shouldered peripheral portion which supports the central portion (1a) above the substrate (2), applying a mask (6) over at least a part of the central portion (1a) and converting the unmasked portion (1b) of the diaphragm to a dielectric so as to electrically isolate the masked central portion (1a) of the diaphragm from the substrate (2).