High-throughput ab initio calculations on dielectric constant and band gap of non-oxide dielectrics

High-k dielectrics, materials having a large band gap (E_g) and high dielectric constant (k) simultaneously, constitute critical components in microelectronic devices. Because of the inverse relationship between E_g and k, materials with large values in both properties are rare. Therefore, massive databases on E_g and k will be useful in identifying optimal high-k materials. While experimental and theoretical data on E_g and k of oxides are accumulating, corresponding information is scarce for non-oxide dielectrics with anions such as C, N, F, P, S, and Cl. To identify promising high-k dielectrics among these material groups, we screen 869 compounds of binary carbides, nitrides, sulfides, phosphides, chlorides, and fluorides, through automated ab initio calculations. Among these compounds, fluorides exhibit an E_g-k relation that is comparable to that of oxides. By further screening over ternary fluorides, we identify fluorides such as BiF₃, LaF₃, and BaBeF₄ that could serve as useful high-k dielectrics.