Effects of Cr dopant on microstructure and properties of
Cu films on Si(100)
Cu films on Si(100)
(Key Laboratory of the Ministry of Education for High Temperature Materials and Testing, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China)
Abstract: The thin films of pure Cu and Cu-2.18%Cr (mole fraction, %) were deposited on Si(100) substrates. Then the samples were vacuum-annealed at 573−773 K to investigate the effect of Cr on the microstructural and electrical characteristics of Cu/Si systems. The XRD results reveal that the annealed Cu(Cr) film has a strong (111) texture. The results of AFM and FESEM indicate that the Cu(Cr) films with insoluble Cr have compact surface morphology and fine columnar microstructure. Upon annealing, most Cr segregates at the surface and interface. The residual insoluble Cr is enriched in amorphous structure between Cu grains and retards the crystallization of annealed Cu(Cr) films. As a result, the minimal annealing resistivity of the Cu-2.18%Cr film is 2.76 μΩ·cm at 773 K, which approaches to 2.55 μΩ·cm of the Cu film at 673 K. Significant changes in the microstructure and properties are obtained by adding Cr to Cu films after annealing.
Key words: Cu(Cr) films; annealing; texture; thermal stability; segregation