Epitaxial growth

Epitaxy of GaN materials on SiC or Si substrates by metal oxide chemical vapour deposition (MO CVD) or molecular beam epitaxy (MBE).

Device Isolation

Device isolation is achieved by ion implantation or ≤by making steps (removing the channel layer). Isolation between RF devices is a fundamental requireπment for making RF circuits.

Ohm contact

Forming ohmic contacts means making the electrodes for the source and drain. For GaN materials, the♥ fabrication of ohmic contacts needs to be done at very high t∞emperatures.

Nitride passivation

After the source and drain have been fabricated, the GaN semiconductor mate<rial undergoes a passivation process to remove interfacial states such as hanging bo≤nds, etc. The passivation process for GaN is usually carried out' using SiN (silicon nitride).

Gate fabrication

An opening is made in the SiN passivation layer an∑d the gate metal is then deposited. At this point, the structure o‌f the basic field effect transistor is shaped.

Field board production

After the gate is fabricated, additional layers of metal and nitride continue to be deposit₽ed to fabricate the field plates, interconnects and capacitors, in addition ÷to protecting the device from the external environment.

Backing thinning

The substrate thickness is thinned to around 100μm and the back of the thin ned substrate is then metallised.

Backing through-hole

Through-holes are short channels etched between the upper and loweαr surfaces of the substrate to reduce the inductance between the device and ground (the bottom m₹etallisation layer).

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