Hafnium oxide deposition (CVD)

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

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

Precursor injection

Vapor pressure

Introduce TDEAH gas into the deposition chamber using a bubbling system, use N₂ as the carrier gas.

To prevent liquefaction of the source before it enters the deposition chamber, maintain the line from the bubbler to the chamber at a temperature of 85°C.

Oxidizer injection

CVD setup

Have O₂ in N₂ in a ration 1:99 and feed it into the chamber through a separate nozzle, because otherwise the O₂ decomposes the TDEAH before it can reach the substrate.

Substrate temperature

Set a temperature between 300°C and 450°C, in order to control deposition speed.

CVD chamber pressure

Set the pressure within the CVD chamber to 1 torr