Influence of N[sub 2]O plasma treatment on microstructure and thermal stability of WN[sub x] barriers for Cu interconnection

Kou-Chiang Tsai, Wen-Fa Wu, Jen-Chung Chen, Te-Jen Pan, Chuen-Guang Chao
2004 Journal of Vacuum Science & Technology B Microelectronics Processing and Phenomena  
Thermal stabilities of Cu-contacted n ϩ -p junctions with tungsten nitride (WN x ) diffusion barriers deposited at various nitrogen flow ratios are investigated. N 2 O plasma treatment is applied to improve thermal stability and barrier performance of WN x film. Sheet resistance of Cu/N 2 O plasma-treated WN x /Si is fairly stable even after annealing at 750°C for 30 min. Moreover, N 2 O plasma treatment enables the Cu/WN x /n ϩ -p junction diodes to sustain thermal annealing at 600°C without
more » ... ectrical degradation. Auger electron spectroscopy depth profiles show that Cu diffusion through the N 2 O plasma-treated WN x barrier is extremely limited, even after annealing at 675°C. Analyses of transmission electron microscopy and x-ray photoemission spectroscopy show that nitridation and oxidation on the WN x barrier occur and an amorphous layer is formed after N 2 O plasma treatment.
doi:10.1116/1.1715087 fatcat:nukdonbnjjacpmqqv3dtym75ya