Structural degradation of thin HfO2 film on Ge during the postdeposition annealing

Abstract

Articles you may be interested inEffect of substrate bias and oxygen partial pressure on properties of RF magnetron sputtered HfO2 thin films J. Vac. Sci. Technol. B 32, 03D104 (2014); 10.1116/1.4825234 Electrical characterization of atomic-layer-deposited hafnium oxide films from hafnium tetrakis(dimethylamide) and water/ozone: Effects of growth temperature, oxygen source, and postdeposition annealing J. Vac. Sci. Technol. A 31, 01A127 (2013); 10.1116/1.4768167 Optical and structural properties of SiO x films grown by molecular beam deposition: Effect of the Si concentration and annealing temperature J. Appl. Phys. 112, 094316 (2012); 10.1063/1.4764893Influence of chemical composition and deposition conditions on microstructure evolution during annealing of arc evaporated ZrAlN thin films Securing the thermal robustness of thin hafnium oxide ͑HfO 2 ͒ film on the semiconductor surface is an important technical issue in the fabrication of the metal-oxide-semiconductor field-effect transistor devices, as the HfO 2 -based high-k gate stacks usually undergo high-temperature processes. In this study, the structural development of thin HfO 2 film on a Ge surface during postdeposition annealing in an ultrahigh vacuum was examined to explore the origin for the initial degradation of thin HfO 2 film. Void nucleation and subsequent two-dimensional void growth take place at 780-840°C, while the chemical composition of the remaining Hf oxide is virtually stable. Both the void nucleation and growth processes show similar larger activation energy of about 10 eV. Based on the observed manner of void growth and the estimated activation energies, the authors propose that mass transport on the HfO 2 surface is responsible for void nucleation in the HfO 2 films on Ge. The authors also compare the present results with the previous studies on HfO 2 / Si structures, and suggest that similar surface process leads to the local Hf silicidation.

Study of Direct-Contact HfO2/Si Interfaces

“…Under low O 2 pressure conditions (<10 −6 torr), on the other hand, local silicidation took place at temperatures higher than 800 °C [ 16 ]. Atomistic mass transfer on the HfO 2 surface led to local thinning of the HfO 2 layer, and this resulted in the formation of voids [ 23 , 24 ]. Hf silicide was formed in these voids due to the reaction of HfO 2 with mobile Si atoms on the void surfaces (HfO 2 + 4Si → HfSi 2 + 2SiO↑) [ 25 ].…”

Growth Behavior, Lattice Expansion, Strain, and Surface Morphology of Nanocrystalline, Monoclinic HfO2 Thin Films

“…Hafnium oxide (HfO 2 ) is a high-temperature refractory material with excellent physical and chemical properties, which makes them promising for a wide variety of technological applications. − The outstanding chemical stability, electrical and mechanical properties, high dielectric constant, and wide band gap of HfO 2 make it suitable for several industrial applications in the field of electronics, magneto-electronics, structural ceramics, and optoelectronics. − HfO 2 has been identified as one of the most promising materials for the nanoelectronics industry to replace SiO 2 because it has a high dielectric constant and is expected to be stable in contact with Si. − …”

“…The controlled growth and manipulation of specific crystal structures at the nanoscale dimensions have important implications for the design and applications of HfO 2 . , However, it is well-known that the optical, electrical, and electro-optic properties of HfO 2 are highly dependent on the surface/interface structure, morphology, and chemistry, which in turn controlled by the fabrication technique, growth conditions, and postfabrication processes. − From the viewpoint, the ability to tailor the properties so as to optimize performance requires a detailed understanding of the geometric structure, particularly at the nanoscale dimensions, of HfO 2 . Furthermore, stabilizing the specific phases with the desired crystallite size, strain, and distribution of grain size characteristics in a controlled way requires detailed understanding of the structural characteristics of nanocrystalline HfO 2 films.…”

Lateral RF MEMS capacitive switch based on HfO<inf>2</inf> film for millimeter wave applications

“…Recently, the HfO 2 film has greatly attracted people's attention because of the excellent physical, electronic, and chemical properties [8][9]. The outstanding conformal coverage, chemical stability, electrical and mechanical properties, high dielectric constant, and wide band gap of HfO2 make it suitable for several industrial applications in the fields of electronics and optoelectronics [10].…”