Growth of uniform diamond-like carbon thin films
Abstract
Diamond thin films are currently one of the hottest topics in materials science. Numerous applications have been envisioned for this material because of its superlative properties such as extreme hardness (it is the hardest material known), very low conductivity (one of lowest known), high thermal conductivity and high optical transparency to name a few. Synthesis of diamond films started with high-temperature, high-pressure (HTHP) devices. This posed a problem because diamond growth seems to be more expensive than a natural one but recently, a certain technique started growing these films at a relatively lower temperature and pressure. Chemical vapor deposition has been the most widely used technique since then. CVD diamond has great advantages over HTHP since it consumes less power and growth occurs at lower temperatures, making it suitable for coating materials with melting temperatures greater than 800°C. This still poses a problem since some materials still evaporate at this low temperature. In the process of diamond film research, many scientists discovered a metastable state of diamond, which they coined as diamond-like carbon. This state contains sp3-sp2 bonds of carbon in contrast to the perfect sp3 bonding of diamond. Researchers took notice of this film and found out that its hardness and optical transparency are still nearly the same as that of CVD diamond. A surprising result is that it can be grown at temperatures much lower than that of diamond CVD (around 200°C) and this makes it possible to grow a material that is nearly as hard and as transparent as CVD diamond on materials with melting temperatures greater than 200°C. This work aims to deposit a uniform diamond-like-carbon film on a silicon substrate utilizing a modified plasma enhanced chemical vapor deposition device.
