【摘要】：課題組在研究Ti-Si-N薄膜結(jié)構(gòu)的基礎(chǔ)上提出了一種新穎的單晶式多晶體（SingleCrystal Like Poly Crystalline，SCLPC）納米金剛石復合結(jié)構(gòu)。本文采用了以密度泛函理論為基礎(chǔ)的第一性原理計算方法考察了Diamond/Si納米復合薄膜中的界面結(jié)構(gòu)；為了確定界面中硅粒子的具體情況，在研究界面的基礎(chǔ)上又研究了4C1Si島構(gòu)型的演變行為；在計算4C1Si島演變過程中碳硅原子遷移激活能發(fā)現(xiàn)，碳原子從閉環(huán)橋位遷移到開環(huán)橋位非常困難，這種情況會造成薄膜生長不均勻。為了解決該問題，本文計算了在納米金剛石薄膜中摻入不同粒子（B、P、N、C、Si、Cu、Ag）后碳原子的遷移激活能，以此來找出一種能夠促進碳原子遷移的粒子。在實驗方面運用微波等離子化學氣相沉積方法制備了四組納米金剛石薄膜，并且運用AFM、Raman設(shè)備檢測了制備得到的金剛石薄膜表面的形態(tài)容貌和薄膜成分。主要得到如下結(jié)論： （1）單層硅界面能夠穩(wěn)定在金剛石（001）表面生長，然而在單層硅界面上進行金剛石薄膜的二次形核和生長時，界面結(jié)構(gòu)遭到嚴重破壞，所以這種單層硅界面結(jié)構(gòu)不能夠穩(wěn)定存在于該復合薄膜中。通過計算四種碳和硅原子比例為1:1的SiC界面結(jié)構(gòu)可以發(fā)現(xiàn)，碳原子在二聚體閉環(huán)橋位和硅原子在二聚體開環(huán)橋位所形成的單層SiC界面與碳原子在二聚體開環(huán)橋位和硅原子在二聚體閉環(huán)橋位所形成的單層SiC界面是同一種界面結(jié)構(gòu)，且該界面結(jié)構(gòu)相對于其他界面結(jié)構(gòu)穩(wěn)定。同時該界面不僅能夠穩(wěn)定生長在金剛石（001）表面，且有利于薄膜生長過程中的二次形核。所以在Diamond/Si復合薄膜中沉積過程中可以形成這種單層SiC界面。 （2）在金剛石（001）重構(gòu)表面通過研究4C1Si島構(gòu)型的演變行為得到硅粒子不能穩(wěn)定待在金剛石晶體內(nèi)部，，而是遷移出來存在于金剛石晶粒的邊緣處；而且金剛石晶粒中的碳原子相比于硅原子遷移特別困難，所以硅粒子更容易在金剛石表面遷移。 （3）在金剛石（001）重構(gòu)表面通過計算一個碳原子和一個摻雜原子（1C1M）組成的島構(gòu)型中碳原子和摻雜原子的遷移激活能可以得出：在2C島中，碳原子遷移需要5.9154eV的激活能。加入銅粒子能夠較明顯的減小碳原子的遷移激活能為3.1126eV。然而相比于島中的碳原子，島中的銅原子更容易遷移為1.5775eV。這就會造成在加入銅粒子后碳原子不遷移而薄膜中的銅原子不停的遷移，起不到對碳原子遷移的促進作用；對于剩余摻雜粒子，碳原子的遷移激活能變化不明顯，而且所需激活能量太大，不符合實驗情況，因此本文所選的幾種摻雜粒子不能夠很好促進碳原子的遷移，需要進一步研究其它粒子對碳原子遷移的促進情況。 （4）其它制備工藝參數(shù)一致，選取500℃、650℃、800℃、850℃四種溫度制備了金剛石薄膜，通過拉曼圖譜得出薄膜中主要成分為金剛石。通過比較薄膜的表面形態(tài)可以得出：隨著溫度增加，薄膜中晶粒聚集能力增強，薄膜表面的粗糙度減小。在850℃時，薄膜中(100)晶向的粒子趨于主導地位，晶粒呈現(xiàn)片狀結(jié)構(gòu)。而且，沉積溫度為800℃時薄膜中金剛石成分含量最多。
[Abstract]:On the basis of the study of the structure of Ti-Si-N thin film, a new type of SingleCrystal Like Poly Crystalline (SCLPC) nanodiamond composite structure was proposed by the research group. The interface structure in the Diamond/Si nanocomposite film was investigated by the first principle calculation method based on the density functional theory. The specific situation of silicon particles in the interface is determined. On the basis of the research interface, the evolution behavior of 4C1Si Island configuration is also studied. In the calculation of the evolution of 4C1Si Island, the transfer activation of carbon and silicon atoms can be found that the migration of carbon atoms from the closed loop bridge position to the open loop bridge position is very difficult. This situation will cause the uneven growth of the film. In this paper, the transfer activation energy of carbon atoms in nano diamond films (B, P, N, C, Si, Cu, Ag) is calculated. In order to find a particle that can promote the migration of carbon atoms, four groups of nanoscale diamond films are prepared by microwave plasma chemical vapor deposition, and AFM and Raman equipment are used in the experiment. The morphology and film composition of the prepared diamond films were measured.
(1) the monolayer silicon interface can grow steadily on the surface of the diamond (001). However, when the diamond films are nucleated and grown on the monolayer silicon interface, the interface structure is seriously damaged, so the monolayer silicon interface structure is not stable in the composite film. The SiC boundary of 1:1 is calculated by the calculation of the ratio of four carbon and silicon atoms to 1:1. The surface structure can be found that the single-layer SiC interface formed by the carbon atom in the closed loop bridge position of the two polymer and the silicon atom in the two polymer open ring bridge position is the same interface structure with the carbon atom in the two polymer open ring bridge position and the silicon atom formed in the closed loop bridge position of the two polymer, and the boundary structure is stable to the other interface structures. The interface can not only grow steadily on the surface of the diamond (001), but also be beneficial to the two nucleation of the film during the growth process, so this monolayer SiC interface can be formed during the deposition of Diamond/Si composite film.
(2) on the reconstructed surface of diamond (001), by studying the evolution of the configuration of 4C1Si Island, it is found that silicon particles are not stable in the diamond crystal, but are migrated to the edge of the diamond grains, and the carbon atoms in the diamond grains are especially difficult to migrate to the silicon atoms, so the silicon particles are more likely to be in the diamond table. Surface migration.
(3) the transfer activation energy of carbon atoms and doped atoms in the island configuration of a diamond (001) reconstructed surface by calculating a carbon atom and a doped atom (1C1M) can be obtained: in the 2C Island, the transfer of carbon atoms requires the activation energy of 5.9154eV. The addition of copper particles can obviously reduce the activation energy of the carbon atoms to be 3.1126eV.. Compared with the carbon atom in the island, the copper atom in the island is more easily migrated to 1.5775eV., which causes the non-stop migration of copper atoms in the film after the addition of copper particles, which does not promote the migration of carbon atoms. For the remaining doped particles, the transfer activation energy of the carbon atoms is not obvious, and it needs to be excited. The active energy is too large and does not conform to the experimental conditions. Therefore, several doped particles selected in this paper can not promote the migration of carbon atoms well. It is necessary to further study the promotion of the transfer of carbon atoms by other particles.
(4) the other preparation process parameters are consistent, the diamond films are prepared at 500 degrees C, 650, 800, 850 temperature, and the main component of the film is diamond by the Raman spectrum. By comparing the surface morphology of the film, it can be concluded that the grain aggregation ability of the film increases with the increase of the temperature, and the roughness of the film surface decreases. In 85, the surface roughness of the film decreases. 85 At 0 C, the (100) orientation particles in the films tend to dominate, and the crystalline grains are flaky. Moreover, the content of diamond in the films is the highest at 800 C.
【學位授予單位】：內(nèi)蒙古科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：O613.71;TB383.2

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