Epitaxial gallium nitride alloy ferroelectronics

1 . A method of fabricating a heterostructure, the method comprising:

providing a substrate; and

implementing a non-sputtered, epitaxial growth procedure at a growth temperature to form a wurtzite structure supported by the substrate, the wurtzite structure comprising an alloy of gallium nitride, the non-sputtered, epitaxial growth procedure being configured to incorporate a group IIIB element into the alloy;

wherein the growth temperature is set at a level such that the wurtzite structure is monocrystalline to an extent that the wurtzite structure exhibits a breakdown field strength greater than a ferroelectric coercive field strength of the wurtzite structure.

2 . The method of claim 1 , further comprising forming a semiconductor layer supported by the substrate before implementing the non-sputtered, epitaxial growth procedure such that the wurtzite structure is formed on the semiconductor layer.

3 . The method of claim 2 , wherein forming the semiconductor layer comprises forming a gallium nitride layer on the substrate.

4 . The method of claim 2 , wherein forming the semiconductor layer comprises growing the semiconductor layer in an epitaxial growth chamber in which the non-sputtered, epitaxial growth procedure for the wurtzite structure is implemented such that the substrate is not removed from the epitaxial growth chamber between forming the semiconductor layer and implementing the non-sputtered, epitaxial growth procedure.

5 . The method of claim 1 , further comprising forming a semiconductor layer after implementing the non-sputtered, epitaxial growth procedure such that the semiconductor layer is in contact with the wurtzite structure.

6 . The method of claim 5 , wherein forming the semiconductor layer comprises growing the semiconductor layer in an epitaxial growth chamber in which the non-sputtered, epitaxial growth procedure for the wurtzite structure is implemented such that the substrate is not removed from the epitaxial growth chamber between implementing the non-sputtered, epitaxial growth procedure and forming the semiconductor layer.

7 . The method of claim 1 , wherein the group IIIB element is scandium.

8 . The method of claim 7 , wherein the scandium has a content falling in a range from about 0.31 to about 0.41.

9 . The method of claim 1 , wherein the substrate comprises sapphire.

10 . The method of claim 1 , wherein the growth temperature is about 600 degrees Celsius or lower.

11 . The method of claim 1 , wherein the non-sputtered, epitaxial growth procedure has a nitrogen-to-metal flux ratio greater than 1.

12 . The method of claim 1 , wherein a III/V ratio of the non-sputtered, epitaxial growth procedure is set to avoid Ga droplet formation.

13 . The method of claim 12 , wherein the III/V ratio falls in a range from about 0.8 to about 0.85.

14 . The method of claim 1 , wherein a Ga beam flux of the non-sputtered, epitaxial growth procedure is fixed during implementation of the non-sputtered, epitaxial growth procedure.

15 . A method of fabricating a heterostructure, the method comprising:

providing a substrate; and

implementing a non-sputtered, epitaxial growth procedure to form a wurtzite structure supported by the substrate, the wurtzite structure comprising an alloy of gallium nitride, the non-sputtered, epitaxial growth procedure being configured to incorporate a group IIIB element into the alloy;

wherein a growth temperature of the non-sputtered, epitaxial growth procedure is set to a level such that leakage paths in the wurtzite structure are reduced to an extent that the wurtzite structure exhibits a breakdown field strength greater than a ferroelectric coercive field strength of the wurtzite structure.

16 . The method of claim 15 , wherein the non-sputtered, epitaxial growth procedure is configured such that the wurtzite structure is monocrystalline.

17 . The method of claim 15 , wherein:

the growth temperature is about 600 degrees Celsius or lower; and

the non-sputtered, epitaxial growth procedure has a nitrogen-to-metal flux ratio greater than 1.

18 . The method of claim 15 , wherein a III/V ratio of the non-sputtered, epitaxial growth procedure is set to avoid Ga droplet formation.

19 . A method of fabricating a heterostructure, the method comprising:

providing a substrate; and

implementing a non-sputtered, epitaxial growth procedure to form a wurtzite structure supported by the substrate, the wurtzite structure comprising an alloy of gallium nitride, the non-sputtered, epitaxial growth procedure being configured to incorporate a group IIIB element into the alloy;

wherein a growth temperature and a III/V ratio of the non-sputtered, epitaxial growth procedure are set such that the wurtzite structure exhibits a breakdown field strength greater than a ferroelectric coercive field strength of the wurtzite structure.

20 . The method of claim 19 , wherein:

the non-sputtered, epitaxial growth procedure is configured such that the wurtzite structure is monocrystalline;

the growth temperature is about 600 degrees Celsius or lower; and

the III/V ratio falls in a range from about 0.8 to about 0.85.