Low dislocation density group III nitride layers on silicon carbide substrates and methods of making the same

Patent metadata

Field	Value
Publication number	US-9331192-B2
Application number	US-16947105-A
Country	US
Kind code	B2
Filing date	Jun 29, 2005
Priority date	Jun 29, 2005
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

Group III nitride semiconductor device structures are provided that include a silicon carbide (SiC) substrate and a Group III nitride epitaxial layer above the SiC substrate. The Group III nitride epitaxial layer has a dislocation density of less than about 4×10 8 cm −2 and/or an isolation voltage of at least about 50V.

First claim

That which is claimed is:

1. A semiconductor device structure, comprising:
a silicon carbide substrate; and
a gallium nitride (GaN) layer having a first surface adjacent the silicon carbide substrate and a second surface opposite the first surface above the silicon carbide substrate having a dislocation density that is less than about 4×10 8 cm −2 and an isolation voltage in a range between about 50 V and about 150V, wherein the GaN layer includes a transition metal dopant in a concentration range between about 2×10 16 cm −3 and 2×10 18 cm −3 that decreases within this range from the first surface towards the second surface by a factor of about 10 approximately every 0.4 μm in the GaN layer and has a thickness in a range between about 5 microns and about 20 microns.

2. The semiconductor device structure of claim 1 , wherein the dislocation density of the GaN layer is less than about 3×10 8 cm −2 .

3. The semiconductor device structure of claim 1 , wherein the dislocation density of the GaN layer is less than about 2×10 8 cm −2 .

4. The semiconductor device structure of claim 1 , wherein the transition metal dopant is selected from a group consisting of Fe, Co, Mn, Cr, V, Cu and Ni and mixtures thereof.

5. The semiconductor device structure of claim 1 , wherein the transition metal dopant comprises Fe.

6. The semiconductor device structure of claim 1 , wherein the semiconductor device structure comprises a device wafer having a diameter of at least about 3 inches.

7. The semiconductor device structure of claim 1 , wherein the semiconductor device structure comprises a device wafer having a diameter of at least about 100 millimeters.

8. The semiconductor device structure of claim 1 , further comprising at least one nucleation layer disposed between the silicon carbide substrate and the GaN layer.

9. The semiconductor device structure of claim 8 , wherein the at least one nucleation layer is selected from a group consisting of aluminum gallium nitride (AlGaN) layers and aluminum nitride (AlN) layers.

10. The semiconductor device structure of claim 8 , further comprising a Group III nitride epitaxial layer on the GaN layer having a composition sufficiently different from the GaN layer to generate a two dimensional electron gas at an interface between the GaN layer and the Group III nitride epitaxial layer.

11. The semiconductor device structure of claim 10 , wherein the two dimensional electron gas has an electron mobility and wherein the semiconductor device structure further comprises at least a second Group III nitride epitaxial layer above the Group III nitride epitaxial layer for increasing the electron mobility in the two dimensional electron gas.

12. The semiconductor device structure of claim 11 , wherein the Group III nitride epitaxial layer comprises Al x Ga 1-x N, wherein 0≦x≦1, and the second Group III nitride epitaxial layer comprises aluminum gallium nitride having different atomic fractions of aluminum and gallium from the Group III nitride epitaxial layer.

13. The semiconductor device structure of claim 11 , further comprising at least one strain management layer disposed between the silicon carbide substrate and the GaN layer having an associated strain which minimizes cracking of the GaN layer.

14. The semiconductor device structure of claim 1 , wherein the silicon carbide substrate comprises a polytype selected from 3C, 4H, 6H and 15R polytypes of silicon carbide.

15. The semiconductor device structure of claim 1 , wherein the silicon carbide substrate is not patterned.

16. The semiconductor device structure of claim 1 , wherein the isolation voltage of said GaN layer is at least about 50V at 1 mA per mm of current flow.

17. The semiconductor device structure of claim 1 , wherein the isolation voltage of said GaN layer is measured over a distance of 5 μm.

18. The semiconductor device structure of claim 1 , wherein the concentration range of the transition metal dopant decreases from about 2×10 18 cm −3 at the first surface to about 2×10 16 cm −3 towards the second surface.

19. The semiconductor device structure of claim 1 , wherein the GaN layer has a dislocation density greater than about 10 8 cm −2 .

20. A semiconductor device structure, comprising:
a silicon carbide substrate;
a Group III nitride heterostructure over the silicon carbide substrate comprising a gallium nitride (GaN) layer over the silicon carbide substrate having a first surface adjacent the silicon carbide substrate and a second surface opposite the first surface wherein the GaN layer has an isolation voltage in a range between about 50V and about 150V, and a Group III nitride epitaxial layer over the GaN layer that is sufficiently different in composition from the GaN layer to generate a two dimensional electron gas at their interface, wherein the GaN layer includes a transition metal dopant in a concentration range between about 2×10 16 cm −3 and 2×10 18 cm −3 that decreases within this range from the first surface towards the second surface by a factor of about 10 approximately every 0.4 μm in the GaN layer and a thickness in a range between about 5 microns and about 20 microns; and
a plurality of respective source, drain and gate contacts in conductive relationship to the Group III nitride hetero structure.

21. The semiconductor device structure of claim 20 , wherein the GaN layer has a dislocation density in a range between about 10 8 cm −2 and about 4×10 8 cm −2 .

22. The semiconductor device structure of claim 21 , wherein the dislocation density of the GaN layer is less than about 3×10 8 cm −2 .

23. The semiconductor device structure of claim 21 , wherein the dislocation density of the GaN layer is less than about 2×10 8 cm −2 .

24. The semiconductor device structure of claim 21 , wherein the transition metal dopant is selected from a group consisting of Fe, Co, Mn, Cr, V, Cu and Ni and mixtures thereof.

25. The semiconductor device structure of claim 21 , wherein the transition metal dopant comprises Fe.

26. The semiconductor device structure of claim 20 , wherein the semiconductor device structure comprises a device wafer having a diameter of at least about 3 inches.

27. The semiconductor device structure of claim 20 , wherein the semiconductor device structure comprises a device wafer having a diameter of at least about 100 millimeters.

28. The semiconductor device structure of claim 20 , further comprising at least one nucleation layer disposed between the substrate and the GaN layer.

29. The semiconductor device structure of claim 28 , wherein the at least one nucleation layer is selected from a group consisting of aluminum gallium nitride (AlGaN) layers and aluminum nitride (AlN) layers.

30. The semiconductor device structure of claim 20 , wherein the two dimensional electron gas has an electron mobility and wherein the semiconductor device structure further comprises a further Group III nitride epitaxial layer above the GaN layer for increasing the electron mobility in the two dimensional electron gas.

31. The semiconductor device structure of claim 30 , wherein the Group III nitride epitaxial layer comprises Al such that the Group III nitride epitaxial layer comprises Al x Ga 1-x N, wherein 0<x≦1, and the further Group III nitride epitaxial layer comprises aluminum gallium nitride havi

Assignees

• Saxler Adam William
• Cree Inc

Inventors

• Saxler Adam William

Classifications

• H10D62/8503

  Nitride Group III-V materials, e.g. AlN or GaN · CPC title

• H10D62/8325

  Silicon carbide · CPC title

• H10D30/4755 Primary

  having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs · CPC title

• H01L29/7787 Primary

  Electricity · mapped topic

• H01L29/2003

  Electricity · mapped topic