Agnitron Imperium Ga2O3, GeO2 Growth

Kathy Anderson (kathy.anderson@utah.edu)

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The Agilis MOCVD system is capable of growing crystalline material layers.  It uses a fully automated and programmable chemical vapor delivery system to direct metal-organic precursors onto a substrate on a rotating, heated chuck in a chamber held at sub atmospheric pressure.  Materials recently grown are Gallium Oxide (Ga2O3) and Germanium Oxide (GeO2).  Samples/substrates up to 2″ diameter can be used.

Reference Documents

Agnitron Agilis MOCVD SOP

Sapphire Orientations

Kilovolt Class Beta Ga2O3 Field-Plated Schottky Barrier Diodes with MOCVD-Grown Intentionally 10^15 cm-3 Doped Drift Layers

Subsequent Processing with Ga2O3

Etch of substrates with a Ga2O3 layer is done in the Plasmatherm.  This is because Chlorine is among the gases fed to the Plasmatherm, and Chlorine is needed to clean the chamber walls to prevent cross contamination of Gallium from one run to the next.

Caution:  Etching Ga2O3 without Chlorine will result in Gallium embedded in the polymer that builds on the walls of the etch chamber during processing.  If this polymer is embedded with Gallium, that Gallium outgases during subsequent runs, unintentionally doping with Gallium exposed samples until a full chamber clean is performed.

Metal deposition onto Ga2O3 is generally done in the e-beam evaporator.

Dicing of sapphire is slow requiring long dicing process times.  Dicing of Ga2O3 on sapphire is even more difficult.  To prevent delamination in sheets, photoresist is spun onto the Ga2O3 layer, softbaked, and then the substrate is inverted and diced photoresist side down.