Amorphous stability of HfO_2 based ternary and binary composition spread oxide films as alternative gate dielectrics

摘要

A ternary alloyed thin film library of HfO_2-Y_2O_3-Al_2O_3 was grown on a Si(100) substrate in a few hours by a new pulsed laser deposition (PLD) system installed with a masking and substrate rotating scheme. This specially designed combinatorial ternary composition spread method enabled us to fabricate continuous ternary and binary composition spread film libraries. It is noteworthy that the library made by this system is addressable; each film composition covers the full range (from 0 to 100%) and can be directly correlated with the film location in the ternary and binary phase diagram. Rapid permittivity measurement on the film libraries was carried out by a scanning microwave microscope, while the crystal structure was by a combinatorial X-ray diffractometer (XRD). The (HfO_2)_6(Y_2O_3)_1(Al_2O_3)_3 ternary composition area in an amorphous phase was found to have a dielectric constant higher than HfO_2-Y_2O_3 binary area. This ternary oxide is promising as amorphous gate dielectric material.