Self Assembly of Magnetic Nanoclusters in Diamond-Like Carbon: A Diffusion Enhanced Process Activated by Collision Cascades

Improvements in device performance are limited by our capabilities in fabrication techniques. To overcome the current barriers, we need a method to atomically position and configure impurities in sub-micron scale devices. Our recent investigations show that this may be possible. By using hydrogen as atomic “lubricants” during ion implantation, we were able to engineer the position of dopants/impurities in near surface region of semiconducting materials in nanometre level precision. We are currently studying cobalt implantation into diamond-like carbon (DLC) system. The implantation profile of cobalt ions matched theoretical prediction when DLC was lacking of hydrogen. However, when hydrogen was introduced into the base material, the implantation profile was found to be strikingly different. On closer examination it was found that that the impurity atoms track the profile of hydrogen within the material. This brings us to an interesting hypothesis: the physical and chemical interaction between the impurities and the hydrogen atoms allows rearrangement of the impurities by increasing their mobility. The remarkable aspect of this result is that the dopants were manipulated using a room temperature process. This ability will have wide implications for many industries such as: engineering dopant profiles in semiconductor devices, positioning magnetic nanoparticles in magnetic sensors and data storage devices, increasing the capacity of hydrogen storage for fuel cell applications.