Growth of nanostructure of transition metal alloy nitride and carbide

Abstract

Transition metal carbide and nitride thin film were grown by magnetron sputtering technique. They were new generation materials to be used as protective layer and metal gate in metal oxide semiconductor device, respectively. For chromium zirconium nitride films, the nitrogen partial pressure in the process was varied to 0 to 100% to study to find the optimized condition. The result showed the chromium zirconium film grown at 20% of total pressure had a maximum hardness and modulus values. The metallic composition of films could be controlled by varying the magnetron current of the targets while the nitrogen partial pressure was kept constant at 20% nitrogen partial pressure. The results indicated that the solid solution could be formed. The hardness of films also related to the preferred orientation of the crystal. The films were annealed at 300, 500 and 700 ℃ to investigate the thermal stability of films. The hardness values tended to increase with an increase in the annealing temperature. The mechanical properties of films could be improved by using the ion assistance during the growth. Tantalum yttrium carbide, which is a candidate for negative metal oxide semiconductor, was grown on hafnium based high-k dielectric material. The composition of yttrium in films could be controlled by varying the power that supplied of TaC and Y targets. The yttrium contents in films also affected the structural, resistivity and flat band voltage shift in the devices. The structure of Tantalum yttrium carbide (TaC)[subscript 1-x]Y[subscript x] films keep face center cubic structure in x value ≤ 0.4 and disorder crystalline in x value ≥ 0.5. The resistivity of (TaC)[subscript 1-x]Y[subscript x] films is almost constant in x value ≤ 0.5 even after annealing at 600 ℃. The flat band voltage can be controlled in the range of 0.5 V by varying x value ≤ 0.5 on hafnium oxide and Hafnium silicate in the post-annealing condition balow 500 ℃. The effective work function may increase due to large amount of the oxygen.