Hafnium oxide deposition (CVD): Difference between revisions

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The equipment required for this process are a CVD and a plasma cleaner for removing impurities after the Hafnium oxide deposition
The equipment required for this process are a CVD and a plasma cleaner for removing impurities after the Hafnium oxide deposition


===Chemical properties of Hafnium-Tetrachloride===


[[File:34591.png|200px|left]]
HfCl<sub>4</sub> can be produced by several related procedures:
*The reaction of carbon tetrachloride and hafnium oxide at above 450&nbsp;°C;
:HfO<sub>2</sub>  +  2 CCl<sub>4</sub>  →  HfCl<sub>4</sub>  +  2 COCl<sub>2</sub>
*Chlorination of a mixture of HfO<sub>2</sub> and carbon above 600&nbsp;°C using chlorine gas or sulfur monochloride:
:HfO<sub>2</sub>  +  2 Cl<sub>2</sub>  +  C  →  HfCl<sub>4</sub>  +  CO<sub>2</sub>
*Chlorination of hafnium carbide above 250&nbsp;°C.
The result of those chemical reactions is a crystalline powder with a melting point of 432&nbsp;°C


===Processing steps===
===Processing steps===

Revision as of 14:19, 12 October 2022

The equipment required for this process are a CVD and a plasma cleaner for removing impurities after the Hafnium oxide deposition


Processing steps

Since HfCl4 is a solid salt at room temperature, we need to first create a liquid precursor, and use direct liquid injection for using it in our CVD.

The process is based on a Japanese paper and requires a complex precursor.

The synthesis of this the Hf precursor TDEAH (Hf(NEt2)4) is so complex, that it needs its own page.

Links

Study HfO2 formation: https://iopscience.iop.org/article/10.1149/MA2005-02/13/547/pdf

A Japanese paper how they grew it with an LPCVD: http://www.trichemical.com/topics/Manuscript%20revisions.pdf