Hafnium carbide formation in oxygen deficient hafnium oxide thin films

Rodenbücher, C.; Alff, L.; Breuer, Uwe; Szot, K.; Waser, R.; Komissinskiy, P.; Sharath, S. U.; Kurian, J.; Hildebrandt, E.

doi:10.1063/1.4954714

Journal Article

FZJ-2016-03415

Hafnium carbide formation in oxygen deficient hafnium oxide thin films

Rodenbücher, C. ; Hildebrandt, E. ; Szot, K.FZJ* ; Sharath, S. U. ; Kurian, J. ; Komissinskiy, P. ; Breuer, U.FZJ* ; Waser, R.FZJ* ; Alff, L.

2016
American Inst. of Physics Melville, NY

Applied physics letters 108(25), 252903 - (2016) [10.1063/1.4954714]

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Please use a persistent id in citations: http://hdl.handle.net/2128/17303 doi:10.1063/1.4954714

Abstract: On highly oxygen deficient thin films of hafnium oxide (hafnia, HfO2− x) contaminated with adsorbates of carbon oxides, the formation of hafnium carbide (HfCx) at the surface during vacuum annealing at temperatures as low as 600 °C is reported. Using X-ray photoelectron spectroscopy the evolution of the HfCx surface layer related to a transformation from insulating into metallic state is monitored in situ. In contrast, for fully stoichiometric HfO2 thin films prepared and measured under identical conditions, the formation of HfCx was not detectable suggesting that the enhanced adsorption of carbon oxides on oxygen deficient films provides a carbon source for the carbide formation. This shows that a high concentration of oxygen vacancies in carbon contaminated hafnia lowers considerably the formation energy of hafnium carbide. Thus, the presence of a sufficient amount of residual carbon in resistive random access memory devices might lead to a similar carbide formation within the conducting filaments due to Joule heating.

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