Hafnium interdiffusion studies from hafnium silicate into silicon

Abstract

The interdiffusion of Hf and Si from high-κ gate dielectric candidate (HfO2)1−x(SiO2)x thin films deposited on Si (100) was studied using x-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, high resolution transmission electron microscopy, and Rutherford backscattering spectrometry in combination with chemical etching. After extreme rapid and conventional furnace thermal annealing treatments, Hf incorporation into Si is limited to less than 0.5–1 nm from the interface. Implications for high-κ gate dielectric applications are also discussed.

Analytical TEM characterization of the interfacial layer between ALD HfO2 film and silicon substrate

“…Furthermore, in agreement with EDS, EELS could not detect any Hf in the interfacial layer. The result is consistent with a previous study showing no substantial Hf diffusion into Si at temperatures below 1000 1C [18].…”

MOCVD of Hafnium Silicate Films Obtained from a Single‐Source Precusor on Silicon and Germanium for Gate‐Dielectric Applications

“…The tail of the Hf signal penetrating the Si substrate is a known measurement artifact. [12] In contrast, for thin films (sample F, thickness of 5.6 nm) depth profiling reveal homogenous, but Si-rich layers with a Hf/Si ratio of almost 1:1 after RTA. Taking the Hf/Si ratio of about 6:1 obtained for as-deposited layers into account, additional Si from the substrate has to be incorporated into thin films during RTA.…”

Oxygen reaction-diffusion in metalorganic chemical vapor deposition HfO2 films annealed in O2

“…Previous studies 1 in other high-k ultrathin films on Si indicated that the interface layer thickness and composition can vary according to the deposition method and routine, and various species can be transported during post deposition thermal processing, like oxygen, 9,10 Si, [11][12][13] and the metal species, 14,15 altering the atomic concentrations as well as chemical composition of the system and consequently electrical characteristics like dielectric constant, interface density of states, and mobility of charge carriers in the transistor channel. In particular, stability against annealing in O 2 -containing atmospheres is of high interest, since in further processing steps it is either performed intentionally to improve leakage current and CET characteristics 1,7,8 or unintentionally, because oxygen is almost always residual in any production furnace.…”