Hf precursor TDEAH (Hf(NEt2)4): Difference between revisions

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[https://download.libresilicon.com/papers/HafniumOxide.pdf Japanese paper]
This is the structure of the organic precursor for Hafnium oxide deposition in a CVD ([[Hafnium_oxide_deposition_(CVD)]])


[[File:TDEAH.png|200px]]
[[File:TDEAH.png|200px]]
as described in the following [https://download.libresilicon.com/papers/HafniumOxide.pdf Japanese paper]
<span style="color:red">
<b>WARNING!</b>
This chemical reacts VIOLENTLY with water and humidity in general!
Caution is required when dealing with it!
</span>
===Chemical properties of Hafnium-Tetrachloride===
The base of this chemical recipe and processing is Hafnium-Tetrachloride, as it can be seen in the picture.
[[File:High-Quality-Hafnium-Chloride-Hafnium-Tetrachloride-Hfcl4-CAS-No-13499-05-3-with-Best-Price.jpg|200px|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
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.
==Atmospheric requirements==
Since this mixture and its components react with oxygen and humidity, we need to use a Schlenk tube setup for mixing it, because we can only do it in an inert atmosphere.
==Chemical reaction==
We combine lithium diethylamide (Et<sub>2</sub>NLi) with Hafnium tetrachloride (HfCl<sub>4</sub>), using a Schlenker tube setup.
With a temperature of 117°C and a pressure of 0.04 torr the following reaction will occur within an inert atmosphere (Argon/Nitrogen):
HfCl<sub>4</sub> + Et<sub>2</sub>NLi
TDEAH (Hf(NEt<sub>2</sub>)<sub>4</sub>)
The yield typically is around 60%
The waste products will be some carbon hydrates (not the stuff in white bread)

Latest revision as of 14:37, 12 October 2022

This is the structure of the organic precursor for Hafnium oxide deposition in a CVD (Hafnium_oxide_deposition_(CVD))

TDEAH.png

as described in the following Japanese paper

WARNING! This chemical reacts VIOLENTLY with water and humidity in general! Caution is required when dealing with it!

Chemical properties of Hafnium-Tetrachloride

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

Hafnium-Tetrachloride


34591.png


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.

The result of those chemical reactions is a crystalline powder with a melting point of 432 °C

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.


Atmospheric requirements

Since this mixture and its components react with oxygen and humidity, we need to use a Schlenk tube setup for mixing it, because we can only do it in an inert atmosphere.

Chemical reaction

We combine lithium diethylamide (Et2NLi) with Hafnium tetrachloride (HfCl4), using a Schlenker tube setup.

With a temperature of 117°C and a pressure of 0.04 torr the following reaction will occur within an inert atmosphere (Argon/Nitrogen):

HfCl4 + Et2NLi → TDEAH (Hf(NEt2)4)

The yield typically is around 60%

The waste products will be some carbon hydrates (not the stuff in white bread)