First principles reaction processes of Co(CO)3NO as an atomic layer deposition precursor on SiO2 and Co surfaces

Abstract

As devices continue to scale down in size, new patterning and deposition techniques are growing in interest. Atomic layer deposition (ALD) has shown to have promising results in selective and low-temperature deposition processes with high conformality and atomic layer control. These properties have led to the increased dependence on ALD process for device fabrication. To further achieve low-temperature deposition, electron enhanced ALD (EE-ALD) has been introduced. EE-ALD is shown to be a viable option for depositing films at room temperature as a way to supplement the thermal energy otherwise needed to overcome activation energies in the deposition process. Furthermore, metals such as Co and Ru are shown to have promising results in replacing Cu lines while using smaller barriers and liners, thus increasing the effective cross section of the conducting interconnect. The reduction in the barrier and liner needed to inhibit dielectric diffusion is responsible for an improved conductivity in Co and Ru lines when compared to Cu with total cross sections below 250 nm2. This work focuses on first principles and atomistic modeling studies on the reaction processes which occur in the deposition of Co films using the precursor Co(CO)3NO and how EE-ALD is used to reduce the deposition temperature. The roles of electron enhancement are investigated for possible electronic excitations of precursor molecules and local surface heating mechanisms.