Highly selective atomic layer deposition of MoSiOx using inherently substrate-dependent processes

A resistive MoSiOx film was deposited with high selectivity on Si in preference to SiO2 and SiN using MoF6, Si2H6 and O-2 as reactants. Two different approaches were demonstrated via thermal atomic layer deposition (ALD). First, ALD of MoSiO(x )by sequential dosing of MoF6, Si2H6 and O-2 (ABC-type) at 200 degrees C followed by an ex-situ post-deposition anneal (PDA) in O-2 at 350 degrees C was performed. The growth of the film using the ABC-type deposition was limited to similar to 5.25 +/- 0.5 nm because the insulating film inhibits the MoF6 and Si2H6 ALD reaction. The second method was to grow MoSix at 120 degrees C and employ a post-deposition anneal in O-2/He at 350 degrees C (AB + C-type) to form MoSiOx. The selectivity of this process on Si versus SiO2 was perfect for 10 nm of deposition on Si, as there were no nuclei or particle formation observed on the SiO2 surface by atomic force microscopy (AFM). The high selectivity can be obtained due to the inherent inability of MoF6 to react SiO2 and SiN surfaces. Transmission electron microscopy (TEM) of a nanoscale-patterned sample demonstrated that the highly selective MoSiOx can be achieved and be integrated into three-dimensional nanoscale structures.