Study of metal gate deposition by magnetron sputtering

A systematic study on metal gate deposition by magnetron sputtering is presented. The authors compared the interface trap density (Dit) in metal-oxide-semiconductor capacitors with metal gate deposited by either conventional magnetron sputtering, atomic layer deposition followed by conventional sputter deposition, or a newly developed magnetron sputtering technology. The results indicate that the new sputtering technology can minimize plasma damage to the underlying ultrathin dielectric film and achieve Dit values of less than 1011cm−2eV−1. Experimental data on plasma characterization using ion collectors and Langmuir probe are presented. The effects of metal gate deposition methods, dielectric film thickness, and sputtering parameters such as sputtering power, pressure, and pulsed dc sputtering are discussed. It is found that pulsed dc sputtering generates higher Dit values. In the new sputtering process, the flux and the energy of the ions arriving at the substrate surface are several times lower, and t...