Granted Patent B2

US 9,054,233 · App. 14/298,263 · Granted Jun 9, 2015

Abstract

Claims (62)

1. A method of making a light emitting device, comprising:

providing a growth substrate comprising a growth mask having a plurality of first apertures in a first area and a plurality of apertures in a second area;

selectively growing a plurality of first nanostructures through the first apertures and a plurality of second nanostructures through the second apertures in a same nanostructure growth step, wherein the first and the second nanostructures comprise an inner portion or an entirety of respective first and second growth templates;

growing first and second active regions on respective first and second growth templates in the same active region growth step; and

growing first and second junction forming elements on respective first and second active regions in a same junction forming element growth step to form respective first and second light emitting devices; wherein

each first growth template differs from each second growth template such that each second light emitting device has a second peak emission wavelength different from a first peak emission wavelength of each first light emitting device; and

the first and the second light emitting devices comprise light emitting diodes, and each first and second junction forming element is selected from a semiconductor shell, a continuous semiconductor layer which contacts plural growth templates, or a continuous semiconductor layer with interstitial voids which contacts plural growth templates.

2. The method of claim 1 , wherein:

each first nanowire core comprises a first conductivity type semiconductor material;

each second nanowire core comprises the first conductivity type semiconductor material;

each first active region comprises at least one first quantum well having a first band gap;

each second active region comprises at least one second quantum well having a second band gap different from the first band gap;

each first junction forming element comprises a semiconductor material of a second conductivity type different from the first conductivity type to form a p-n or p-i-n junction with the first growth template and the first active region; and

each second junction forming element comprises a semiconductor material of the second conductivity type different from the first conductivity type to form a p-n or p-i-n junction with the second growth template and the second active region.

3. The method of claim 2 , wherein each first growth template differs from each second growth template by at least one of: (a) a growth area for a respective active region, (b) a ratio of exposed growth planes, (c) a spacing from adjacent growth templates, or (d) a size of the aperture in the growth mask.

4. The method of claim 3 , wherein:

each first and second nanowire core comprises a III-nitride semiconductor material;

each first and second quantum well comprises an indium gallium nitride material; and

each first quantum well contains a different amount of indium from each second quantum well due to the difference between the first and the second growth templates in at least one of: (a) the growth area for a respective active region, (b) the ratio of exposed growth planes, (c) the spacing from adjacent growth templates, or (d) a size of the aperture in the growth mask.

5. The method of claim 4 , wherein:

each first growth template comprises the first nanowire core and at least one first template layer around the first nanowire core, such that the first template layer extends laterally beyond the first aperture over the growth mask;

each second growth template comprises the second nanowire core and at least one second template layer around the second nanowire core, such that the second template layer extends laterally beyond the second aperture over the growth mask;

each first growth template has a nanopyramid shape;

each second growth template has a nanopillar or nanowire shape;

each first growth template has a larger p-plane facet area contacting the first active region than a p-plane facet area of the second growth template contacting the second active region; and

each first quantum well contains a higher amount of indium and a lower peak emission wavelength than each second quantum well due to the difference in the p-plane facet area between the first and the second growth templates.

6. The method of claim 5 , wherein:

each first and second III-nitride semiconductor nanowire core is selectively grown by MOCVD in a group V limited growth regime;

each first aperture has a substantially equal width or diameter to each second aperture;

each first aperture is spaced farther apart from adjacent first apertures than each second aperture is spaced apart from adjacent second apertures; and

each first growth template has a substantially equal or smaller growth area contacting the first active region than a growth area of each second growth template contacting the second active region.

7. The method of claim 6 , wherein:

the first and the second III-nitride semiconductor nanowire cores are grown in the group V limited growth regime in combination with a sufficiently high density of apertures in the second area and a sufficiently high growth temperature to warrant an increase in III-nitride mediated catalytic cracking of ammonia group V source material in the second area; and

each first growth template has the smaller growth area contacting the first active region than the growth area of each second growth template contacting the second active region.

8. The method of claim 6 , further comprising forming a plurality of third light emitting devices located over a third area of the substrate, each third light emitting device has a third peak emission wavelength different from the first and the second peak emission wavelength.

9. The method of claim 8 , wherein:

each third light emitting device contains a third nanopyramid growth template comprising a third nanowire core which protrudes through third aperture in a growth mask in the third area;

each third aperture has a substantially equal width or diameter to each first and second aperture;

each third aperture is spaced farther apart from adjacent third apertures than each first and second apertures are spaced apart from adjacent respective first and second apertures;

each third growth template has a substantially equal or smaller growth area contacting a third active region than a growth area of each first and second growth template contacting the respective first and second active regions; and

the third peak emission wavelength is longer than the first and the second peak emission wavelengths.

10. The method of claim 5 , wherein:

each first aperture has a substantially larger width or diameter than each second aperture;

each first aperture is spaced substantially equal or farther apart from adjacent first apertures than each second aperture is spaced apart from adjacent second apertures; and

each first growth template has a substantially the same or smaller growth area contacting the first active region than a growth area of each second growth template contacting the second active region.

11. A method of making a semiconductor device, comprising:

providing an intermediate semiconductor structure comprising a substrate, a plurality of first III-nitride semiconductor growth templates comprising a first III-nitride semiconductor nanostructure located over a first area of the substrate, and a plurality of second III-nitride semiconductor growth templates comprising a second III-nitride semiconductor nanostructure located over a second area of the substrate, wherein each first growth template differs from each second growth template by at least one of: (a) a growth area for a respective active region, (b) a ratio of exposed growth planes, or (c) a spacing from adjacent growth templates;

growing first and second indium gallium nitride semiconductor active regions on respective first and second growth templates in a same active region growth step; and

growing first and second semiconductor junction forming elements on respective first and second active regions in a same junction forming element growth step to form respective first and second light emitting devices;

wherein each first active region contains a different amount of indium from each second active region due to the difference between the first and the second growth templates in at least one of: (a) the growth area for a respective active region, (b) the ratio of exposed growth planes, or (c) the spacing from adjacent growth templates.

12. The method of claim 11 , wherein the step of growing first and second indium gallium nitride semiconductor active regions comprises using MOCVD using an ammonia group V material source.

13. A method of growing a III-V semiconductor nanowire, comprising growing the III-V nanowire over a substrate by MOCVD in group V limited growth regime; the method further comprising:

growing a plurality of first III-V nanowires by MOCVD in the group V limited growth regime through first apertures in a first area of a growth mask located over the substrate, and a plurality of second III-V nanowires by MOCVD in the group V limited growth regime through second apertures in a second area of a growth mask, wherein each first aperture is spaced further apart from adjacent first apertures than each second aperture, and wherein the first III-V nanowires have a smaller height than the second III-V nanowires; and

growing at least one first III-V semiconductor template layer over the first III-V nanowires to form a plurality of first growth templates, and growing at least one second III-V semiconductor template layer over the second III-V nanowires to form a plurality of second growth templates, wherein each first growth template differs from each second growth template by at least one of: (a) a growth area for a respective active region, (b) a ratio of exposed growth planes, or (c) a spacing from adjacent growth templates.

14. The method of claim 13 , further comprising:

growing a first active region comprising at least one first indium gallium nitride quantum well on the first growth template;

growing a second active region comprising at least one second indium gallium nitride quantum well on the second growth template; and

growing first and second junction forming elements on respective first and second active regions;

wherein each first quantum well contains a different amount of indium from each second quantum well due to the difference between the first and the second growth templates.

15. The method of claim 14 , wherein:

the first and the second III-V nanowires comprise III-nitride nanowires which are grown in the group V limited growth regime in combination with a sufficiently high density of second apertures in the second area and a sufficiently high growth temperature to warrant an increase in III-nitride mediated catalytic cracking of ammonia group V source material in the second area; and

each first growth template has the smaller growth area contacting the first active region than the growth area of each second growth template contacting the second active region.

Assignments (10)