Key issues on interface control of the constituent materials are taken up and reviewed with respect to scaled logic and memory. For logic devices with high-k/metal gate, amount of oxygen vacancy in the high-k dielectric determines the effective workfunction by modulating the workfunction derived from the high-k/metal gate materials. Concerning the EOT control of HfO2, by controlling the oxidation time of pre-deposited metal-Hf, precise thickness control of the interfacial layer including no interface layer with excellent uniformity is achieved. In the meantime, for a magnetic tunnel junction (MTJ) for spin-transfer-torque switching, a redox reaction is found to occur at the surface of Ta/CoFeB/MgO/CoFeB where the oxidized cobalt and iron are reduced by the boron atoms that diffuse toward the top CoFeB surface. It is imperative to protect the MTJ surface from oxidation/ hydroxylation to obtain an accurate tunnel current.