直流靜電式微型振動發電機之分析、設計與製作

Abstract

由於近年來在低功率VLSI以及CMOS技術的發展，積體電路的能量需求已經降低至數十□W的程度，由環境獲取能量來驅動低功率的遠端感測器成為可能。微機電系統是一個整合機械元件與電子電路的平台，在全世界的發展日漸流行。藉由使用微機電系統科技，具有整合電子元件的機械能量獲取器已具有提供低功率元件能量的能力。 本論文中，我們提出了對於一直流式振動至電能轉換器的新穎設計與分析方法。在一平方公分的晶片面積及40V輸出電壓的限制下，由3.6V電壓以及120Hz振動源驅動，最佳化的輸出功率在有外加4克質量塊以及無外加質量塊的情況下分別為40.5 uW以及0.87 uW。 本元件是在SOI晶圓上利用深矽蝕刻技術製作。與先前的元件做比較，應用低壓氣相沉積技術所沉積的氮化矽薄膜提升了梳齒結構的絕緣能力。在利用高精準度陰影遮罩的定義下，元件接腳以及開關側向包覆改由金作為沉積材料，解決了先前使用鋁所造成的氧化問題，同時也減少了漏電電阻的產生。利用激振器所測量的共振頻率與設計值相符。元件的可變電容以及寄生電阻皆已量測，其可變電容範圍為94pF至485pF，寄生電阻由103M歐姆提升為156M歐姆。機械式接觸開關經由測試已經確認其可正常工作。然而，由於不垂直的梳齒結構，能量轉換的過程中只產生較低的電壓。輸出功率的測量仍然在進行中。

Energy scavenging from ambient environment becomes feasible to power independent remote sensors or portable devices due to low power VLSI and CMOS technology development. The requirement of power consumption has been reduced to a few tens of microwatts. Micro-Electro-Mechanical System (MEMS) is a platform that integrates mechanical devices with electric circuit. The development of MEMS is increasingly popular in the world. By using MEMS technology, a mechanical energy harvester with electric component is capable of supplying those low power devices. In this thesis, the novel design and modeling method as well as the fabrication and measurement of a DC capacitive vibration-to-electric energy converter are introduced. With the device area constraint of 1 , bias by a 3.6V battery, output voltage limited to 40V, and operation frequency of 120Hz, the optimum output power is 40.5uW and 0.87uW for devices with and without a 4 gram external mass attachment, respectively. The device was fabricated in SOI wafers with deep silicon etching technology. Compared with previous devices, LPCVD nitride improved the isolation of fingers. Gold pads and switch lateral coverage defined by the high precision shadow mask had reduced the aluminum oxidation problem and reduced the leakage resistance. The resonant frequency measured by a shaker agreed with our design value. Variable capacitance of 94pF to 485pF was measured. The parasitic resistance was improved from 103M omhto 156M□omh□ The mechanical contact switch was test and workable. However, due to non vertical combs fingers, lower voltage was generated in the conversion process. The output power measurement is still in progress.