Study on the electrical characteristics of MgO & Graphene tunnel junctions for spintronics device applications스핀트로닉스 소자를 위한 MgO 및 그래핀 터널접합의 전기적 특성에 관한 연구
For the development of high performance spintronics devices, the fabrication of tunnel barrier with high quality is a critical issue. Currently, MgO barrier is known to be the best candidate for high tunnel spin polarization. So far, MgO barrier of high quality re-quired MBE system, which provides high quality MgO film, but is very high in cost and slow in process. Thus to succeed in chip integration of spintronics devices with CMOS technology and other electronic system, study on fabricating MgO barrier with industrial friendly method is necessary. In this study, MgO tunnel barrier is deposited on germanium (Ge) substrate by sputtering method. A little twist in fabrication method has been intro-duced in this study in order to successfully sputter MgO thin film on Ge substrate. Another candidate for tunnel barrier is graphene. Graphene is a single atomic layer of carbon with honeycomb lattice structure. This ultra-thin film of carbon can provide very uniform and thin layer of tunnel barrier for tunnel junctions. In this study, graphene is used as the tun-nel barrier between ferromagnetic metal and Ge substrate to find out the feasibility of gra-phene as the tunnel barrier for spin injection.