A Fully Integrated Microbattery For An Implantable Microelectromechanical System

摘要

The Wireless Integrated Microsystems Engineering Research Center's Intraocular Sensor (WIMS-ERC IOS) was studied as a model system for an integrated, autonomous implantable device. In the present study, we had four objectives: (1) select and designing an optimized power supply for the WIMS-IOS; (2) develop a fabrication technique allowing small scale, low-cost, and integrable fabrication for CMOS systems, and experimentally demonstrate a microscopic power source; (3) map capacity and lifetime of several fabricated microbatteries; (4) determine the effects of miniaturization on capacity, lifetime and device architecture. Physical vapor deposition (PVD) was used to deposit thin layers (≤ 1 μm) of metal sequentially onto glass substrates (SiO_2, as used in the device). To map the influence of size over cell capacity and cycle life, we fabricated and tested five stand-alone cells using a Solartron~R 1470E battery tester and a Maccor~R 4000 series tester. A sixth battery was fabricated to investigate the effects of system integration, variable discharge rate and size reduction simultaneously. The highest experimental capacity among the larger cells O(cm~2) was 100 μAh, achieved by IOS-C-1 at 250 μA (1.4C) discharge. Among 0(mm~2) cells, IOS-M-1 achieved the highest capacity (2.75 μAh, ～76% of theoretical) at 2.5 μA discharge (0.7 C rate).