Plasma enhanced atomic layer deposition of manganese nitride thin film from manganese amidinate and ammonia plasma

Abstract

Manganese nitride films have been successfully fabricated by the technique of plasma enhanced atomic layer deposition (PEALD). The process employed bis(N,N'-di-tert-butylacetamidinate)manganese [Mn(amd)2] as manganese precursor and ammonia plasma as a coreactant. With a typical PEALD process cycle of 5 s Mn(amd)2 pulse, 10 s Ar purge pulse, 10 s NH3 plasma exposure, 10 s Ar purge pulse, 80 °C deposition temperature, and 60 W input power, the deposited film is continuous and smooth with a growth rate is 0.037 nm/cycle. Based on x-ray diffraction measurement, the film is determined to be η-Mn3N2 crystal structure. The primary deposition mechanism has been investigated by in situ optical emission spectroscopy and quartz crystal microbalance. The deposited manganese nitride film shows an excellent barrier performance against copper diffusion at insulator/copper interface.