ABSTRACT
Complex oxides are preferred because their desirable electrical properties can be tailored by compromising the material properties of different oxides. Titanium and scandium can form stoichiometric binary alloys or complex oxides with other Transition metal/rare earth metal elements. For a stable complex oxide alloy, the materials must have a compound phase with a congruent melting point; otherwise, chemical phase separation will occur at some temperatures. Silicon oxide, which crystallizes above 1100°C, is an excellent candidate to increase the crystallization temperature of the high-k dielectrics. In many aspects, such as the oxide charge density, the interface properties, and the thermal stability, high-k metal oxides are much poorer than the covalent silicon oxide and silicon nitride. Addition of a more electronegative transition or rare earth metal such as Ti or Sc to the high-k film can increase the metal-oxygen ionicity.
