- 學位論文
微波電漿系統設計及其應用在超奈米微晶鑽石成長之研究
Design of microwave plasma enhanced CVD system and their application in the growth of ultra-nano crystalline diamond film.
摘要
微波電漿共振器的設計主要是要利用化學汽相沉積成長大面積的鑽石薄膜。而微波電漿共振器採用了環形微波偶合技術。首先從一個規格WR340的矩形波導管其中剖面電場分佈必需要有8個半波長，然後將此矩形波導管彎成環形共振結構。隙縫(2.5 mm x 50 mm)的適當位置位於環形共振器上表面電流最大值處，而隙縫主要是讓微波從環形共振器上耦合到環形共振器中間的圓柱石英管內，並且激發電漿。電漿被引用到理想的共振條件中模擬，而其差別是為了確保微波和反應氣體之間充分的耦合。系統機械的結構，主要基於微波模擬時的尺寸而定。最後利用空氣去點起電漿，證明了系統設計為正確無誤的。 此外，在一個相似的實驗程序中，利用Ar/CH4電漿在Si基材上成功地成長超奈米微晶鑽石(UNCD)。其中可以發現合成最好場發射的UNCD其最重要的鍍膜參數有甲烷含量、總壓力和微波功率。在分析方面，SEM在微結構上會有最深切地改變。而Raman光譜對UNCD結構為最不敏感的。在UNCD薄膜擁有最佳的場發射條件為:CH4=1%，微波功率1200 W和總壓力100 Torr。
並列摘要
A microwave plasma reactor was designed for growing large area diamond films by plasma-enhanced chemical vapor deposition process. The annular microwave coupling technique is adopted for designing the microwave plasma reactor. The first step in the reactor designing process is to determine the length (8 half-wavelength) of a rectangular wave guide with WR 340 cross-sectional dimension, bend it to form a annular resonance structure. The slots of proper dimension (2.5 mm x 50 mm) were located at the point of maximum surface current to couple the microwave from the annular resonator to the cylindrical quartz for the purpose of inducing the plasma. Deviation from the ideal resonance condition due to the introduction of plasma was simulated to assure that the sufficient coupling between the microwave and reaction gases. The mechanics of the setup based on the microwave simulation was designed and machined. The induction of air plasma was demonstrated to verify the correctness of the design. Moreover, ultra-nanocrystalline diamond films were successfully grown on Si-substrates using Ar/CH4 plasma in a setup of similar structure. It is found that the most important parameters for synthesizing UNCD films with good electron field emission properties are methane-content, total pressure and the microwave powers. The SEM microstructure changed most profoundly with these parameters, whereas the Raman structure is least sensitive to them. The EFE properties were optimized for the UNCD films grown in the following conditions: CH4=1%, microwave power of 1200 W and total pressure of 100 Torr.