Atomic layer deposition of ultrathin metal-oxide films for nano-scale device applications

With continuous dimensional scaling of high-performance transistors, high-k dielectrics are emerging as a very important research area in Si-based FET (field effect transistor) devices. Additionally, due to the uniquely high film quality, easy thickness controllability down to the nm range, and near perfect conformality, the ALD (atomic layer deposition) technique is also emerging as a future deposition technique for various applications. By combining these two promising areas, it is quite possible to open new application areas besides that of Si-based FETs which is under worldwide study. Recently developed Ge- and GaAs-based transistors with ALD high-k dielectrics have exhibited very promising electrical results, with surface passivation methods showing the possibility to further increase transistor performance. In addition, top-gated molecular devices, such as carbon nanotube and Ge nanowire transistors, were successfully developed with the help of ALD high-k dielectrics. Various other possible applications of ALD high-k dielectrics have also been suggested in this paper.