Electrical Properties of Ultrathin Platinum films by Plasma Enhanced Atomic Layer Deposition.

The ability to deposit thin and conformal films has become of great importance due to down-scaling of devices. However, due to nucleation difficulty, depositing electrically stable and thin conformal platinum film on an oxide nucleation layer has proven challenging. By using Plasma Enhanced Atomic Layer Deposition (PEALD) and TiO2 as a nucleation layer, we achieved electrically continuous PEALD platinum films down to a thickness of 3.7 nm. Results show that for films as thin as 5.7 nm, the Mayadas-Shatzkes (MS) model for electrical conductivity and the Tellier-Tosser model for temperature coefficient of resistance (TCR) hold. Although the experimental values start to deviate from MS model below 5.7 nm due to incomplete Pt coverage, the films still show Root Mean Square (RMS) electrical stability better than 50 ppm over time, indicating that these films are not only electrically continuous but also sufficiently reliable for use in many practical applications.