Effects of fluorine incorporation on the properties of Ge p-MOS capacitors with HfTiON dielectric

In this work, Ge p-MOS capacitors with HfTiON gate dielectric were fabricated by sputtering method. Pre-deposition fluorine plasma treatment and post-deposition fluorine plasma annealing were used to improve the electrical and reliability properties of Ge p-MOS capacitors. Experimental results showed that both methods could improve the interface quality with lower interface-state density, less frequency dispersion, and also enhance the reliability properties with smaller increases of oxide charge and gate leakage after high-field stressing. Compared with pre-deposition fluorine-plasma treatment, post-deposition fluorine plasma annealing achieved higher quality of high-k/Ge interface such as lower interface-state density, higher dielectric constant and lower stress-induced gate leakage current. By XPS and AFM analyses, the improvements should be due to the passivation effects of fluorine on oxygen vacancies, dangling bonds and the dielectric surface.