射頻電漿輔助化學氣相沉積法合成非晶質含氮碳膜

Synthesis of amorphous carbon-nitrogen films by RF plasma enhanced chemical vapor deposition

黃哲晃(Che-Haung Haung)

指導教授 ： 曾信雄 ； 許正勳 ； 何主亮

大同大學/工程學院/材料工程學系所/碩士(2004年)

摘要

本實驗以射頻電漿輔助化學氣相沉積法(RF-PECVD)沉積非晶質碳膜以及非晶質含氮碳膜，藉由改變N2/CH4、氣體總流量、沉積壓力、電漿功率、沉積時間、自偏壓等參數，並以薄膜重量和厚度、拉曼(raman)光譜、X光光電子能譜(XPS)、奈米壓痕測試(nanoindentation)等分析，來探討上述製程參數對薄膜沉積 速率、結構以及硬度值的影響。實驗結果顯示沉積速率隨N2/CH4的提高、氣體總流量的降低、沉積壓力的降低、沉積時間的延長而減少；而隨自偏壓範圍由250 V-300 V提高至335 V-365 V而增加；當N2/CH4<0.75時，沉積速率隨電漿功率提高而增加，反之，當N2/CH4≧0.75時，低電漿功率(100 W)之沉積速率最高。拉曼分析結果顯示薄膜結構不隨氣體總流量和沉積時間而有太大改變；薄膜之類鑽特性隨N2/CH4的提高、沉積氣壓的降低、電漿功率的提高而減低；而隨自偏壓範圍250 V-300 V提高至335 V-365 V薄膜之類鑽特性增加。而所有薄膜之G峰位置(G-position)介於1540-1580 cm-1之間。以電漿功率200 W、氣體總流量30 sccm、沉積壓力0.3 torr沉積薄膜之X光光電子能譜分析顯示含氮碳膜的N/C最高約為0.07，當N2/CH4提高，薄膜的sp3C-C含量減少；在薄膜經1分鐘Ar+濺射後，可使薄膜氧含量減少，且顯示sp2C-C被優先濺射的情形。奈米壓痕測試的測試結果顯示薄膜之硬度值大多和結構分析的結果相呼應，其類鑽特性的優劣明顯影響薄膜之硬度值。硬度值不隨氣體總流量和沉積時間而有太大改變；但隨N2/CH4的提高、沉積壓力的降低、電漿功率的提高而減低；而隨自偏壓範圍250 V-300 V提高至335 V-365 V薄膜之硬度值增加。而所有薄膜之硬度值介於7-19 GPa之間，雖然硬度值隨氮含量之增加而降低，但在某些沉積參數下仍具有類鑽碳膜的硬度值。

關鍵字

非晶質含氮碳膜

並列摘要

Deposition of amorphous carbon and amorphous carbon-nitrogen films by RF-plasma enhanced chemical vapor deposition was studied. The effects of deposition parameters, including N2/CH4 ratio, total flow rate, working pressure, RF power, deposition time and the self bias voltage, will be discussed. We investigate the effects of the parameters on the deposition rate, the structure and the hardness of the films by analyzing the weight and thickness of the films, raman spectroscopy, x-ray photoelectron spectroscopy (XPS) and nanoindentation. The experimental results show that the deposition rate decreases with increasing the N2/CH4 ratio and deposition time, and with decreasing the total flow rate and the working pressure. The deposition rate also increases as the range of the self bias voltage increases from 250 V-300 V to 335 V-365 V. As N2/CH4＜0.75, the deposition rate increases with increasing the RF power. On the contrary, the deposition rate is higher for lower RF power as N2/CH4≧0.75. Analysis of raman spectrum shows that the structure of the films has no obvious change with the total flow rate and deposition time. The characteristics of the films tend to be graphite like with increasing the N2/CH4 ratio and RF power, and with decreasing the working pressure. The characteristics of the films tend to be diamond like as the range of the self bias voltage increases from 250 V-300 V to 335 V-365 V. The position of G band is between 1540 cm-1 and 1580 cm-1. XPS analysis shows that the maximum N/C ratio of the carbon-nitrogen is 0.07 while the film was deposited under a RF power of 200 W, a total flow rate of 30 sccm and a working pressure of 0.3 torr. As N2/CH4 ratio increases, the relative quantity of sp3C-C decreases. XPS analysis also indicates that the oxygen content decreases when the sample was sputtered with Ar+ for 1 min. It is also shown that sp2C-C is preferentially sputtered. The results of nanoindentation are consistent with the results of the structure analysis by raman spectroscopy. In other word, the hardness increases when the ratio of sp3C-C/sp2C-C increases. No obvious change of hardness with the total flow rate and deposition time was found. However, the hardness decreases as the N2/CH4 ratio and RF power are raised, and as the working pressure is decreased. The hardness also increases as the range of the self-bias voltage increases from 250 V-300 V to 335 V-365 V. The hardness of all of the films investigated in this study is between 7 GPa and 19 GPa. Although the hardness decreases as nitrogen content increases, the films still possess the hardness of the DLC films under certain deposition parameters.

並列關鍵字

amorphous carbon-nitrogen films

參考文獻

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