在MEMS元件重視內部腔體氣密性能力的同時，鋁鍺薄膜不失為一種良好的氣密性共晶接合材料，除了可在較低溫下進行接合的優點外，且金屬與半導體接合後形成緻密結構亦是重要因素，因此本研究主要探討Al-Ge薄膜在退火後薄膜表面形貌的觀察與Al-Ge擴散行為之動力學機制。本實驗選用磁控式濺鍍機(Magnetron Sputtering)為鍍膜設備，在壓力約10^-5 Torr下製備a-Ge(100 nm)/Al (100 nm)/Si substrate的雙層膜結構。將試片在真空下封入玻璃管中後分別放入200°C、300°C和400°C之高溫爐管中，退火時間從一天、五天、十天、十五天到二十天，另外製作室溫下的三種試片：剛鍍好的試片、放置十六天以及放置七十天之試片，用以比較室溫下不同時間對Al-Ge薄膜交互擴散之影響。試片分析儀器為掃描式電子顯微鏡(SEM)、能量散佈分析儀(EDS)、X射線光電子能譜儀(XPS)、低掠角X射線繞射儀(GIXRD)。 從XPS以及SEM觀察室溫下時間因素並不會影響薄膜之交互擴散行為；200°C下退火薄膜表面開始出現富鋁區析出物，表示Al-Ge之間進行交互擴散現象；300°C下退火十天薄膜發生層交換 (Layer exchange) 現象，依實驗觀察以及文獻理論探討Al-Ge薄膜層交換之動力學機制，並推測Al原子擴散至Ge表面的主要路徑為Ge的晶界。400°C下退火試片表面出現巨大突起物，應為薄膜升溫過程中承受來自基板壓應力，為釋放應力而向外擠出突起物。 Eutectic alunimun/amorphous-germanium (Al/a-Ge) bilayer thin film is characterized by its remarkable hermetic sealing in wafer-level bonding in microelectromechanical system (MEMS) devices. This study investigates metal-induced crystallization (MIC) of the amorphous Ge and the layer exchange of Al and Ge. The a-Ge(100 nm)/Al(100 nm) bilayer thin films were deposited by sputtering technique and separately sealed in glass tubes in a vacuum of 10^-3 Torr. The samples were analyzed mainly by scanning electron microscopy (SEM), energy dispersive Spectrometer (EDS) analysis, and x-ray photoelectron spectroscopy (XPS). From the results we found that the diffusion behavior was impervious to the time evolution at room temperature. a-Ge began induced crystallization by Al when annealing at 200°C. Layer exchange of Al and Ge occurred at 300°C of annealing for 10 days. A kinetic mechanism is developed to explain the layer exchange phenomenon of Al and Ge system. Extrusions were found on the surfaces of the samples annealed at 400°C due to stress relaxation.
