Effects of pre- and post-microwave annealing treatments on pGe MOS device

Abstract

Effects of pre- and post- microwave annealing (MWA) treatment on electrical characteristics of p-type Ge substrate (pGe) metal-oxide-semiconductor (MOS) devices were investigated in this work. The physical mechanism was studied with an X-ray photoelectron spectroscopy analysis. The pre-MWA treatment, which is similar to conventional post oxidation annealing on interfacial layer (IL), can passivate the oxygen vacancy by chemisorbed oxygen. The excess chemisorbed oxygen atoms may be left at the interface between IL and high-k, which would induce more interface/oxide traps and form more unstable components in IL. The chemisorbed oxygen can be replaced with well-bonded oxygen by using a post-MWA treatment on high-k dielectric , instead of a conventional post deposition annealing. As a result, pGe MOS device with a double-MWA treatment exhibits low equivalent oxide thickness value (~0.65 nm), small frequency dispersion, low interface trap density, and excellent reliability characteristics without increasing the leakage current. The oxygen vacancy passivation and chemisorbed oxygen suppression with a double-MWA treatment are crucial for high performance Ge MOS device and monolithic 3D IC applications. • The effect of pre- and post- microwave annealing (MWA) treatment is compared. • Oxygen vacancy can be passivated by chemisorbed oxygen in pre MWA. • Excess chemisorbed oxygen can be replaced with well-bonded oxygen by post MWA. • A p-type Ge substrate capacitor can be improved by double MWA.