利用直流磁控濺鍍沈積鈷奈米粒子於矽（001）基板上之研究

本研究利用直流磁控濺鍍沈積鈷奈米粒子於矽（001）基板上。製程改變的參數為基板偏壓（+525至-100 Volts），濺鍍靶材到基板間之距離（6～12 cm），以及沈積時間（10～30 sec），其餘的參數皆保持不變，包含濺鍍功率為50瓦等。使用原子力顯微鏡及掃描式電子顯微鏡，以分析鈷奈米粒子之表面型態及尺寸；利用穿透式電子顯微鏡來分析鈷奈米粒子的微結構。本實驗利用直流磁控濺鍍，於室溫下，成功地製作出具分散性的鈷奈米粒子於Si(001)基板上。研究發現，外加基板正偏壓，可獲得數個奈米到數十奈米級尺度的鈷奈米粒子；此較大的多晶鈷奈米粒子，乃由較小的單晶鈷聚集而成，且同時具有面心立方和六方最密堆積等兩相共存。為使奈米粒子之尺寸減小並分佈更均匀，可供給較大的正偏壓予基板，而獲得電荷累積之效應，此時奈米粒子的成長動力學，可由VW成長模式變化成類似SK成長模式。

Dispersive cobalt nanoparticles are fabricated directly on SiO2/Si(001) substrates by DC magnetron sputtering at room temperature. During deposition, the parameters chosen for the investigation are substrate bias (from +525 To -100 Volts), target-to-substrate distance (from 6 to 12 cm) and deposition time (from 10 to 30m sec), while the other parameters are kept the same, including the power of 50 watts. Atomic force microscope (AFM) is employed to determine the density and morphology of cobalt nanoparticles whereas high-resolution electron microscope (HRTEM) is used to visualize the resulting microstructure in the nanoparticles. It is found that Co nanoclusters array ranging from a few nanometers to some tens of nanometers can be fabricated by applying positive substrate bias. The larger polycrystalline cobalt nanoclusters are formed by the coalescence from the smaller single-crystalline ones, where fcc and hcp phases coexist. The size reduction and uniformity of the nanoclusters array can be further enhanced by applying larger positive biases due to electron charging effects. Under charging effects, the growth kinetics can be altered from the VW to SK-1ike growth mode.