Characteristics of Ruthenium Films Prepared by Chemical Vapor Deposition Using Bis(ethylcyclopentadienyl)ruthenium Precursor

We prepared ruthenium thin films by chemical vapor deposition using a liquid bis(ethylcyclopentadienyl)ruthenium precursor in an oxidizing atmosphere, and then investigated the electrical resistivity, thermal stability, and conformality of these films. As a result of amorphous partly forming in the ruthenium film, the electrical resistivity increased with increasing growth temperature and ratio, However, the partial oxides did not affect the intrinsic transport mechanism of electrical conduction. In addition, no change in the morphology of the ruthenium film was observed after heat-treatment at 700°C, even when the partial oxides remained in the as-deposited ruthenium films. Precise control of the growth conditions enabled fabrication of conformal ruthenium electrodes. For example, using a low ratio of 1.3% and a low growth temperature of 230°C or less resulted in excellent step coverage of almost 100%.