Embodiments of the present invention provide improved methods and apparatus suitable for use with hearing devices. A vapor deposition process can be used to make a retention structure having a shape profile corresponding to a tissue surface, such as a retention structure having a shape profile corresponding to one or more of an eardrum, the eardrum annulus, or a skin of the ear canal. The retention structure can be resilient and may comprise an anatomically accurate shape profile corresponding to a portion of the ear, such that the resilient retention structure provides mechanical stability for an output transducer assembly placed in the ear for an extended time. The output transducer may couple to the eardrum with direct mechanical coupling or acoustic coupling when retained in the ear canal with the retention structure.