Materials with a high permittivity, which exceeds that of silicon dioxide( SiO2) with 3.9, belong to the high-k dielectrics. If the permittivity is below that of silicon dioxide, they are low-k dielectrics.
High-k insulating materials are used as gate dielectrics in semiconductor devices such as the MISFETs between the silicon substrate and the gate and in capacitors. High-k dielectrics include silicon nitride( Si3N4) with a permittivity of 7, aluminum oxide( Al2O3) with 9, titanium dioxide ( TiO2) with 80, and hafnium oxide (HfO2).
High-k materials allow electronic components - example: MIS capacitor - and integrated circuits to be built more compactly. Since they have better insulation properties, they cause lower leakage currents and therefore have much lower power losses. In terms of manufacturing, high-k dielectrics can be produced physically by physical vapor deposition( PVD) and also chemically by chemical vapor deposition( CVD).