電漿處理及沉積矽薄膜以改良奈米碳管場發射特性

PLASMA TREATMENT AND SILICON COATING TO IMPROVE THE FIELD EMISSION PROPERTIES OF CARBON NANOTUBES

黃振邦(Chen-Pang Huang)

指導教授 ： 施文欽

大同大學/電機資訊學院/光電工程研究所/碩士(2008年)

摘要

本論文主要有四個部份，首先利用直流濺鍍機台在矽基板上成長催化金屬薄膜，然後再利用熱化學氣相沉積法成長奈米碳管。接著將試片移至一台蝕刻與濺鍍兩用系統中，對試片進行不同氣體的電漿轟擊後處理，改變奈米碳管的性質，最後臨場轉變機台功能變成濺鍍沉積系統，對試片進行矽薄膜的披覆。

利用直流濺鍍機台和熱化學氣相沉積法在氨氣和乙炔的混合氣體中成長奈米碳管，可以非常穩定地成長出品質一致之奈米碳管。在二極式的架構下，陽極和陰極的間隙約為300 μm，測得最好的樣本可在電場強度0.33 V/μm 時達到場發射起始電流密度10 μ A/cm2。

蝕刻與濺鍍兩用系統中，對試片進行不同氣體的電漿轟擊後處理，皆可以降低場發射起始電場10 % ~ 20 % ；氫氣電漿後處理可以增加奈米碳管的缺陷；氮氣電漿後處理除了可以增加奈米碳管的缺陷外，並可去除奈米碳管較長突出的部份與頂端的催化金屬。

利用蝕刻與濺鍍兩用機台的濺鍍功能，沉積不同厚度的矽薄膜，在經過後處理的奈米碳管上沉積約7 nm 的矽，其使用壽命可達33 小時，較未處理過的奈米碳管5.5 小時提升許多。證明後處理製程加上沉積一層矽薄膜，可達到保護奈米碳管並且延長使用壽命的功效。

關鍵字

電漿處理 ； 奈米碳管 ； 批覆

並列摘要

This research has four parts, first we use the DC sputtering apparatus to deposit catalytic metal film on Silicon substrate, and then use thermal chemical vapor deposition(CVD) for the growth of carbon nanotubes(CNTs). Then the specimen was moved into the sputtering and etching dual-use system. The field emission characteristics of CNT could be changed by the bombardment of plasma processing of different gases, the final part we change the dual-use apparatus function into a sputtering deposition system, The silicon film will be deposited onto the CNTs.

The CNTs with sputtering catalyst grown by thermal CVD method with the mixed ammonia and acetylene gas can be very stable and consistent to the quality of the CNTs. Under the diode structure condition, the anode and the cathode gap of 300 μ m, the turn-on electric field of the best sample measured is about 0.33 V / μ m and reached 10 μ A/cm2 which is the turn-on
current density.

In sputtering and etching dual-use system, The turn-on electric field of all CNTs can be reduced 10% to 20% after the bombardment of plasma treatment of different gases. Hydrogen plasma processing can increase the defects of the CNTs; nitrogen plasma processing can increase the defects of the CNTs, removing longer prominent part of the CNTs and removing the catalytic metal on the top of the CNTs.

Deposition by sputtering and etching dual-use system, we deposit different thickness of silicon film on the CNTs after plasma treatment of nitrogen gas. After depositing 7 nm silicon on treated CNTs, the lifetime can be improved to 33 hours. It is much longer compared to untreated CNTs which is 5.5 hours. We can conclude that the CNTs can be protected, and lifetime is extended effectively by the treatment process and addition of silicon thin film.

並列關鍵字

coating ； plasma treatment ； CNT

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