Hafnium oxide deposition (CVD)

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The base of this chemical recipe and processing is Hafnium-Tetrachloride, as it can be seen in the picture.

Hafnium-Tetrachloride

You might notice that Hafnium-Tetrachloride is a solid crystal at room temperature, which is kind of a problem considering that we wanna use it as a vapor in our CVD furnace, in order to react it with oxide for obtaining a Hafnium-Oxide thin film layer.

Chemical properties of Hafnium-Tetrachloride

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HfCl4 can be produced by several related procedures:

  • The reaction of carbon tetrachloride and hafnium oxide at above 450 °C;
HfO2 + 2 CCl4 → HfCl4 + 2 COCl2
  • Chlorination of a mixture of HfO2 and carbon above 600 °C using chlorine gas or sulfur monochloride:
HfO2 + 2 Cl2 + C → HfCl4 + CO2
  • Chlorination of hafnium carbide above 250 °C.[1]

Processing steps

https://patents.google.com/patent/CN100356519C/en

  1. Elinson, S. V. and Petrov, K. I. (1969) Analytical Chemistry of the Elements: Zirconium and Hafnium. 11.