Design and Fabrication of Fully Implantable MEMS Cochlea

Abstract

The micro-electro-mechanical array for application as fully implantable cochlea is presented in this paper. The complete system including a short overview of energy harvesting and the system configuration is proposed. This study mainly covers mechanical properties of cochlea microfabricated silicon structure. Electro-mechanical simulations are proceeded to optimize the material used for resonators, the size of array membranes and to estimate the resistive change due to the input sound signal. The sound is detected by thin Si X N Y diaphragm due to resonant frequency and the displacement of the membrane caused by acoustic pressure. The displacement is detected employing piezoresistive electrodes (NiCr). Design and fabrication process based on MEMS technology are described and discussed. The response measurement of the cochlea structure is performed. The sizes of the membranes vary from (0.5 × 0.5) mm to (2.0 × 2.0) mm and the average current change is 6.55•10 -3 % corresponding to the acoustic pressure of 0.01 Pa.

Materials and Biomedical Applications of Implantable Electronic Devices

“…Reproduced with permission. [ 217 ] Copyright 2015, Elsevier Science BV. d) A camera image of the spiral‐shaped piezoelectric MEMS cantilever array.…”

“…At present, the implantable power supplies and speech processors are already available in clinical products, but the implantable microphones are the difficult point for a breakthrough. In recent years, various forms of fully implantable microphones and electrode arrays are reported, such as the MEMS array system composed of several individual active piezoresistive thin diaphragms and actuated by acoustic waves (Figure 7c), [ 217 ] spiral‐shaped piezoelectric MEMS cantilever array system (Figure 7d), [ 30 ] parylene thin‐film cochlear implant electrode arrays (Figure 7e), [ 218 ] etc. However, to be accepted as a mainstream alternative, many efforts should be spent to provide cochlear implant patients with similar or higher sound quality to their external counterparts.…”

“…No commercially available products. [30,[215][216][217][218][219] Implantable pressure sensors Intraocular pressure sensors Achieving the direct and frequent IOP measurements.…”

“…Reproduced with permission. [ 217 ] Copyright 2015, Elsevier Science BV. Scheme of the implantable wireless ECoG recording system.…”

“…c) The conceptual scheme of the design of fully MEMS cochlear implant system. Reproduced with permission [217]. Copyright 2015, Elsevier Science BV.…”