多晶鑽石膜在光電元件之應用與製程研究

Abstract

我們致力於尋找鑽石成長的新氣體源,結果發現二氧化碳混合碳氫化合物 系有較高成長速率與高成核密度等優點,而且使用此較低的甲烷濃度才能 在低基板溫度成長結晶性之高品質鑽石膜.在鑽石膜的半導體化的研究方 面,我們採用硼酸三甲酯(B(OCH3)3)為摻雜源,在甲烷與二氧化碳之氣體組 成中以微波電漿化學沉積法(microwave plasma chemical vapor deposition,MPCVD),成功地合成p-type的鑽石膜.此外,我們已經研發出一 種改善鑽石膜選擇成長的新製程,及利用光阻或 SiO2當作光罩材料,甲烷 與二氧化碳作為沉積鑽石的氣體源及以HF: HNO3:H20(1:1.1:10)的混合液 為蝕刻溶液,結果顯示較長的蝕刻時間會增加鑽石膜的選擇性. Rescently, we have been searching for a new reaction source in diamond growth. The result shows that diamond with a higher growth rate and improved crystallinity can be deposited wuthout adding extra hydrogen gas to the hydro- carbon feed by using CO2-hydrocarbon gas mixtures. From the results, we can conclude that, to obtain a good quality low tempurature diamond films using CH4-CO2 gas mixtures,it is necessary to reduce the ratio of [CH4]/[CO2]. Boron doped diamond films were fabricated on Si substrate by MPCVD. Tri- methylborate vapor were introduced to the CH4-CO2 gas mixtures as a dopant source. Futhermore, a novel process which employs the photoresist or SiO2 as a mask, the CH4-CO2 gas mixtures as the gas source of diamond deposition and the HF:HNO3:H2O(1:1.1:10)solution acted as etching solution. More the etching time will be result in increasing the selectivity of diamond films growth.