Pt Film Growth with Tetra-Kis(Triflurophosphine)Platinum

Platinum film growth using Pt(PF 3 ) 4 precursors was investigated. The study focused on three aspects of film growth: conformality, adhesion and selective growth. Pt(PF 3 ) 4 deposited pure Pt films over a wide range of temperatures (∼200 to 400 °C). At 200 °C, the step coverage for a via with an aspect ratio of three was poor. Lower growth temperatures showed a significant decrease in the growth rate. In addition, these films had poor adhesion to the substrate as indicated by separation between the Pt and the substrate in cross sectional scanning electron microscopy images. Oxygen addition during Pt film growth from Pt(PF 3 ) 4 improved both film conformality and adhesion. With oxygen, the step coverage on the side wall was greater than 90 % The dependence of the film growth rate on oxygen varied with the growth temperature: the growth rate decreased at 200 °C, while it changed slightly at 260 °C when oxygen was added. The substrate effect on the initial growth rate was studied on various substrates. The initial growth rate on metals is much faster than that on other substrates. The growth rate decreased on various substrates in the order of iridium > titanium nitride > barium strontium titanate > silicon nitride > silicon oxide.