A process is disclosed for fabricating a device with a cavity formed at one end thereof. A body is provided with a depression, and mask layer is applied to the surface of the body and the depression, the mask layer having a lower etch rate than the body. Near the depression, an opening is formed in the mask layer. Starting from the opening, the body is subjected to an isotropic etching process to form the cavity below the mask layer, with the mask layer being essentially preserved and forming in the area of the depression a structure extending into the cavity.