利用不鏽鋼基板製作壓電懸臂樑式微型能量擷取元件之研究

Abstract

本論文主要在利用301不鏽鋼基板製作壓電懸臂樑式微型能量擷取元件。此微型能量擷取元件有能力可以擷取環境周遭的機械振動能，並透過鐵電材料鈦鋯酸鉛(PZT)將其轉換成電能。為了獲得高電壓及功率的輸出，壓電層利用沉積效率高且室溫製程的氣膠沉積法製作。發電的壓電模式主要分成單層壓電d31及雙層壓電模式，此兩種模式可分別開發出輸出特性不同的微型能量擷取元件。此外，在過往研究中，都是利用矽基板製作微型能量擷取元件，但是在低頻率高振幅的使用環境下，矽基板製作的懸臂樑容易斷裂，為了解決此問題，本論文利用301不鏽鋼基板取代矽基板製作微型能量擷取器，另一方面也將不鏽鋼基板與矽基板製作之微型能量擷取器進行輸出特性跟運行壽命的比較。最終透過微機電製程技術，成功製作出三種微型能量擷取元件，包含不鏽鋼基板製作上下電極輸出的d31元件、矽基板製作上下電極輸出的d31元件與不鏽鋼基板製作雙層壓電的d31模式元件。實驗結果顯示，本研究開發的微機電元件最高有能力產生四百微瓦等級的能量，且輸出電壓遠高於全橋整流電路的最低要求。

In the past decade, the vibration energy harvesting technologies based on piezoelectric materials have been studied intensively and been improved constantly. The power outputs of piezoelectric MEMS generators are also steadily improved year by year. This dissertation presents the development of piezoelectric MEMS power generators which have the ability to harvest mechanical energy of surrounding vibrations and transform vibration energy into useful electrical power. The harvesting electrical power is able to use in energy storage applications. To improve and get high- efficiency piezoelectric MEMS generators, the lead zirconate titanate (PZT) material was directly deposited on the substrate by the aerosol deposition method which could deposit PZT thin film up to tens micron in minutes. The piezoelectric MEMS generators utilize the d31 and bimorph of PZT for transforming mechanical strain energy into electrical charge by using. For applications with higher vibration levels, the structure with PZT ceramic fabricated on silicon or SOI substrate may break under higher acceleration levels. To increase the mechanical strength of the piezoelectric MEMS generators structure, alternative substrate material, stainless steel substrate is proposed. Finally, we succeed to fabricate the piezoelectric MEMS generators based on stainless steel, piezoelectric MEMS generators based on silicon and piezoelectric MEMS bimorph generators by means of micro-electro-mechanical-systems (MEMS) process. We also compared the output performance of these devices and the lifetime of these devices in a long-term vibration. Experimental results confirm that the devices have the ability to generate power in the hundred micro-watt range and the output voltage is much higher than the minimum requirement for diode band-gaps in the rectifier circuit.