title: Probing the thermal decomposition behaviors of ultrathin HfO2 films by an in situ high temperature scanning tunneling microscope.
abstract: The thermal decomposition of ultrathin HfO(2) films (∼0.6-1.2 nm) on Si by ultrahigh vacuum annealing (25-800 °C) is investigated in situ in real time by scanning tunneling microscopy. Two distinct thickness-dependent decomposition behaviors are observed. When the HfO(2) thickness is ∼ 0.6 nm, no discernible morphological changes are found below ∼ 700 °C. Then an abrupt reaction occurs at 750 °C with crystalline hafnium silicide nanostructures formed instantaneously. However, when the thickness is about 1.2 nm, the decomposition proceeds gradually with the creation and growth of two-dimensional voids at 800 °C. The observed thickness-dependent behavior is closely related to the SiO desorption, which is believed to be the rate-limiting step of the decomposition process.
authors: Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, SAR. k.xue@unsw.edu.au
authors: Kun
authors: K
authors: Xue
authors: Lei
authors: L
authors: Wang
authors: Jin
authors: J
authors: An
authors: Jianbin
authors: J
authors: Xu
mesh_terms: D003460:Crystallization; D006195:Hafnium / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D046529:Microscopy, Electron, Transmission / Q000379:methods; D016252:Microscopy, Scanning Tunneling / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D010087:Oxides; D017640:Silicates; C545179:hafnium oxide; D012822:Silicon Dioxide; D006195:Hafnium; D012825:Silicon