Effect on thermal stability of a Cu/Ta/Si heterostructure of the incorporation of cerium oxide into the Ta barrier

Abstract

The effects of CeO2 addition on the microstructural change of a Ta diffusion barrier film and thermal stability of the Cu/Ta/Si system were investigated. When a Ta layer was prepared with CeO2 addition, the silicide formation was retarded up to 800 °C. The Cu/Ta+CeO2/Si system retained its structure up to 800 °C without an increase in stack resistivity, while the Cu/Ta/Si structure degraded after annealing at 550 °C. The Ta+CeO2 diffusion barrier showed an amorphous microstructure and chemically strong bonds with Ta–Ce–O. It appeared that the thermal stability of the Cu/Ta+CeO2 interface as well as the Ta+CeO2/Si interface was higher than that of both Cu/Ta and Ta/Si interfaces. Therefore, the Ta film prepared by CeO2 addition effectively prevented the interdiffusion of Cu and Si through the diffusion barrier up to 800 °C.

Enhanced thermal stability of a sputtered titanium-nitride film as a diffusion barrier for capacitor-bottom electrodes

“…1 indicates that the Ru (30 nm)/TiN/doped-poly-Si/Si contact system exhibits behavior similar to that of the Ru (100 nm)/TiN/doped-poly-Si/Si contact system tion and interdiffusion for copper as well as oxygen up to high temperatures. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] The conductive-RuO 2 phase for the Ru/TiN/poly-Si/Si contact system is formed at the surface of the Ru film after postdeposition annealing at 450°C. The Ru at the surface of Ru films exists as RuO x in a nonstoichiometric state.…”

Application of Pd/Ge/Cu alloyed ohmic contact system to n-type GaAs for fully Cu-metallized InGaP/GaAs HBTs

“…Copper has been widely used in metallization for the silicon based very-large scale integration (VLSI) because of its lower electrical resistivity, higher electromigration resistance and lower cost [1][2][3]. However, even though copper metallization has become very popular in the fabrication of Si devices, there are only a few reports on the copper metallization of GaAs devices [4,5].…”

Evaluation of Electrical Characteristics of the Copper Metallized SPDT GaAs Switches at Elevated Temperatures

“…C OPPER has been used instead of aluminum as the interconnect metal for silicon integrated circuit technology since IBM adapted copper metallization in the silicon 0.18-μm technology [1]- [3]. The advantages of using copper metallization for Si technology include low resistivity and high electromigration resistance; however, there are only a few Manuscript received January 15, 2008; revised March 19, 2008.…”