Molybdenum Atomic Layer Deposition Using MoF6 and Si2H6 as the Reactants

Mo ALD has been demonstrated by fluorosilane elimination chemistry using MoF6 and Si2H6 as the reactants. The nucleation and growth characteristics of Mo ALD were investigated using a variety of in situ and ex situ techniques in both high vacuum and viscous flow reactors. Quartz crystal microbalance (QCM) and X-ray reflectivity (XRR) investigations showed that Mo ALD has significant growth rate of 500−600 ng/cm2 per cycle or 6−7 A per cycle for temperatures between 90 and 150 °C. The large growth rates could result from extra Mo deposition by MoF6 → Mo + 3F2 that may be facilitated by the very exothermic reaction of MoF6 with silicon-containing surface species. The QCM studies revealed that the Mo ALD surface chemistry is self-limiting. The QCM and Auger electron spectroscopy (AES) studies indicated that Mo ALD nucleates very rapidly on Al2O3 ALD surfaces and reaches the linear growth regime after only 4−5 ALD cycles. Oscillatory behavior for the total mass gain and individual mass gains was observed vers...