Effect of silicon substrate treatment on the growth of DLC thin film

• Main Authors: Che-min Li, 李哲旻
• Other Authors: Herng-Yih Ueng
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/94669689010122153164

碩士 === 國立中山大學 === 電機工程學系研究所 === 99 === Diamond-like Carbon (DLC) film exhibits an extreme hardness, low friction coefficient, chemical stability, heat conductivity, and high resistance. Their properties lead to remarkable applications on industry. In the experiment, we use electrondeposition to deposit the DLC film on Si substrate. Different concentrations of electrolyte were used to deposit on the of silicon substrates with different roughness surface. KOH solution was used to etch and to get the different roughness on the surface of silicon substrates. the morphology of surface were observed by SEM and AFM. Composition and microstructure of the DLC film were characterized by the Raman spectroscopy and XPS, repectively. The optical properties of DLC film were investigated by the N&K analyzer. From the AFM results, the surface morphology observed by KOH etching on the surface of silicon substrates during etching time as 0、20、40、60 min, the surface roughness increased from 2.64 to 14.07 nm. Based on thevariation of surface roughness, the growth rate was observed more quicker than the non etch surface. Moreover, to deposit the DLC film on the alkalinity solution was better then acid solution. However, the ID/IG ratio and the sp2/sp3 ratio obtained from Raman and XPS increase with the roughness surface from 1.09 to 1.82 and 0.985 to 2.15, respectively. It is because that the microstructure of DLC film varies and exchange to graphitization. The mixed the ammonia water and ammonium acetate into acetic acid solution was used to deposit DLC film on Si surface, and film shows with lower ID/IG ratio. Additionally, as the amount of ammonium acetate was varied in the solution, the ID/IG ratio of the films observed as decrease from 1.2 to 0.93 with increasing amount of ammonium acetate 10g to 40g. It was due to the methyl radicals increase in the solution. Besides, we can find the optical band gap decreased with DLC films changing to graphitization.