Towards the 3-D Microfabrication and Integration of a Complete Power Unit Used for Energy Autonomous Wireless System

This paper deals with the fabrication of an all-solid lithium-ion microbattery for autonomous wireless sensors networks nodes, focusing especially on the solid electrolyte and the negative electrode made of silicon nanowires. Regarding the electrolyte, amorphous thin solid films of lithium phosphorus oxynitride (LiPON) were prepared by radio-frequency sputtering of a mixture target of P 2 O 5-Li 2 O in ambient nitrogen atmosphere. The morphology, composition, and ionic conductivity were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and A.C. impedance spectroscopy. A microstructuring process is proposed, including a double masking with silicon oxide and silicon nitride layers. Finally, the combination of silicon nanowires and LiPON is presented.