Resistivity variation with the grain growth and the boron content in Cu(B) films

Resistivity variations and abnormal grain growth occurred in Cu(B)/SiO2 and Cu(B)/Ti/SiO2 structures which were vacuum-annealed in the 100 - 900 .deg. C temperature range. The resistivity sharply decreased up to 500 .deg. C because of grain growth and boron precipitation. The minimum observed resistivity was 2.37 μΩ-cm obtained from the Cu(B)/Ti/SiO2 structure annealed at 600 .deg. C. An abnormal grain growth was observed in the Cu(B)/SiO2 film annealed at 400 .deg. C. A strong affinity exists between B and Ti, so the presence of Ti in Cu(B)/Ti/SiO2 films significantly decreased the B content and increased growth of Cu(111)-oriented grains, probably driven by Ti glue layer.