Ab InitioDesign of High-kDielectrics:LaxY1−xAlO3

Stephen A. Shevlin, Alessandro Curioni, Wanda Andreoni
2005 Physical Review Letters  
We use calculations based on density-functional theory in the virtual crystal approximation for the design of high-k dielectrics, which could offer an alternative to silicon dioxide in complementary metaloxide semiconductor devices. We show that aluminates La x Y 1ÿx AlO 3 alloys derived by mixing aluminum oxide with lanthanum and yttrium oxides have unique physical attributes for a possible application as gate dielectrics when stabilized in the rhombohedral perovskite structure, and which are
more » ... ure, and which are lost in the orthorhombic modification. Stability arguments locate this interesting composition range as 0:2 < x < 0:4. Phase separation in microdomains is shown to have the tendency to further enhance the dielectric constant. We propose this as a novel family of high-k dielectrics deserving experimental exploration.
doi:10.1103/physrevlett.94.146401 pmid:15904084 fatcat:biumziv45bfunongfmfxbc2r64