奈米平板鑽石沉積在(111)面向鑽石薄膜之研究

Abstract

本實驗主要是利用微波化學氣相沉積法，佐以直流偏壓輔助成核法(BEN)，以Si (111)為基材，期望能夠得到(111)面向的連續鑽石薄膜。另一方面，根據研究，板狀鑽石的成長跟(111)內的雙晶缺陷有關係。所以藉由沉積大量的板狀鑽石在(111)晶面粒上，希望得到板狀鑽石的規則陣列。

實驗中改變多項沉積參數，包括微波功率、偏壓條件、甲烷濃度等等。不同的條件下，表面形貌以及密度會有明顯的改變。經實驗後發現，在較低的成長濃度以及較低的微波功率之下，可以得到良好的(111)面向鑽石。(111)晶面的密度約為108 cm-2，尺寸約為0.3-0.5μm之間。

高溫電漿的情況下，得到密度相當高的板狀鑽石，厚度約4-5 nm。密度約為109 cm-2，邊長尺寸約為250-350 nm。經過觀察，發現到有很高比例的直立板狀鑽石，直立的方向跟(111)晶粒內雙晶面排列的方向相當類似。此外，也有許多板狀排列為相互平行或是夾某個特定角度，根據以上的規律性，我們可以推斷(111)晶粒內的雙晶缺陷主導著板狀鑽石的成長。

Growth of continuous and (111) oriented diamond films on Si (111) substrates are demonstrated using Microwave Plasma Chemical Vapor Deposition with Bias-enhanced Nucleation method. As twins in <111> oriented grains play an important role on the growth of the nano-platelet diamond, they can be uesd to get regular arrays of platelets in vertically standing-up configurations on the (111) textured films. Various deposition parameters, including microwave power, bias conditions, and CH4 concentration have been used to establish optimal conditions for (111) film growth. At lower CH4 concentration and microwave power, it is found that (111) textured diamond films were achieved as shown by SEM. The density of (111) grains is about 108/cm-2 , and the size is about 0.3-0.5μm。 High-density nano-platelet diamonds of 4-5 nm thickness were achieved under high-temperature plasma. The density is about 109/cm2, and the length is about 250-350 nm. From scanning election microscopy examination, we found that most of the nano-platelet diamonds stands up vertically on the surface. From the distribution of diamond nano-platelets with their angular values, therefore, it is suggested that twin planes in the (111) oriented diamonds are the decisive factor. There are many platelets arranged parallel to each other or intersected at a specific angle. According to that, we can suppose that the growth of nano-platelet diamonds is governed by twins generated in (111) oriented grain.