Heterostructure device and associated method

1. A method of manufacturing a heterostructure field effect transistor comprising:

forming a semiconductor multi-layer structure having a plurality of semiconductor layers, wherein forming the semiconductor multi-layer structure includes:

providing a gallium nitride layer; and

disposing an aluminum gallium nitride layer on the gallium nitride layer;

coupling a source electrode to the semiconductor multi-layer structure at a first region of the aluminum gallium nitride layer;

coupling a drain electrode to the semiconductor multi-layer structure at a second region of the aluminum gallium nitride layer;

coupling a gate electrode to the semiconductor multi-layer structure at a third region of the aluminum gallium nitride layer such that the gate electrode is affixed directly to the third region without intervening elements therebetween, the third region being disposed between the first region and the second region;

implanting iodine ions into only the third region of the aluminum gallium nitride layer;

and depleting a charge from a two dimensional electron gas channel in the third region so as to form a reversibly electrically non-conductive pathway from the source electrode to the drain electrode;

wherein applying a voltage potential to the gate electrode coupled to the third region allows electrical current to flow from the first region to the second region.

2. The method of claim 1 further comprising implanting ions of chlorine, bromine, fluorine, or a combination of two or more thereof, into the third region of the aluminum gallium nitride layer.

3. The method of claim 1 further comprising sputtering metallic material onto the first and second regions of the aluminum gallium nitride layer to form the source electrode and the drain electrode.

4. The method of claim 1 wherein the concentration of the iodine ions in the third region is in a range of from about 1×10 13 cm−3 to about 1×10 15 cm−3.

5. The method of claim 1 wherein disposing the aluminum gallium nitride layer comprises epitaxially growing the aluminum gallium nitride layer.

6. The method of claim 1 further comprising applying a silicon dioxide mask to the first and second regions of the aluminum gallium nitride layer.

7. The method of claim 6 further comprising:

providing a source contact pad on the first region of the aluminum gallium nitride layer; and

providing a drain contact pad on the second region of the aluminum gallium nitride layer;

wherein the silicon dioxide mask covers the source contact pad and the drain contact pad.

8. The method of claim 6 wherein implanting iodine ions into the third region of the aluminum gallium nitride layer comprises implanting iodine ions into an area of the aluminum gallium nitride layer not covered by the silicon dioxide mask.

9. The method of claim 8 further comprising removing the silicon dioxide mask upon implanting of the iodine ions into the third region of the aluminum gallium nitride layer.