Controlling pit formation in a III-nitride device
View Patent ↗A device includes a semiconductor structure comprising a III-nitride light emitting layer disposed between an n-type region and a p-type region and a plurality of layer pairs disposed within one of the n-type region and the p-type region. Each layer pair includes an InGaN layer and pit-filling layer in direct contact with the InGaN layer. The pit-filling layer may fill in pits formed in the InGaN layer.
1. A method comprising:
growing a semiconductor structure comprising:
a III-nitride light emitting layer disposed between an n-type region and a p-type region; and
a plurality of layer pairs disposed within one of the n-type region and the p-type region, each layer pair comprising:
an InGaN layer, wherein each InGaN layer has an InN composition between 3% and 10%; and
a pit-filling layer in direct contact with the InGaN layer; and doping each of the pit-filling layers and each of the InGaN layers with an n-type dopant.
2. The method of claim 1 further comprising growing each pit-filling layer at a temperature greater than 900° C.
3. The method of claim 1 wherein each pit-filling layer is GaN.
4. The method of claim 1 wherein each pit-filling layer is AlGaN.
5. The method of claim 1 wherein each pit-filling layer has an AN composition between 3% and 10%.
6. The method of claim 1 wherein each pit-filling layer is AlInGaN.
7. The method of claim 1 wherein each InGaN layer has a thickness between 100 and 500 nm.
8. The method of claim 1 wherein each pit-filling layer has a thickness between 10 and 50 nm.
9. The method of claim 1 wherein growing a semiconductor structure comprises growing at least one of the layer pairs such that a plurality of pits are disposed on a top surface of the InGaN layer in one of the layer pairs and a size of the plurality of pits on the top surface of the InGaN layer is greater than a size of a plurality of pits disposed on a top surface of the pit-filling layer in the same layer pair.
10. The method of claim 1 wherein growing a semiconductor structure comprises growing between 2 and 50 layer pairs.
11. The method of claim 1 further comprising:
removing portions of the light emitting layer and p-type region to expose portions of the n-type region;
disposing a first metal contact on the p-type region; and
disposing a second metal contact on the n-type region;
wherein the first metal contact and the second metal contact are disposed on a same side of the semiconductor structure.
12. The method of claim 1 wherein each pit-filling layer is a substantially single crystal layer.
13. The method of claim 1 wherein growing a semiconductor structure comprises growing at least one pit-filling layer at a temperature that is greater than a temperature at which at least one InGaN layer is grown.
14. The method of claim 1 wherein growing a semiconductor structure comprises growing at least one pit-filling layer at an ammonia concentration that is greater than an ammonia concentration at which at least one InGaN layer is grown.
15. The method of claim 1 wherein growing a semiconductor structure comprises growing at least one pit-filling layer at a growth rate that is slower than a growth rate at which at least one InGaN layer is grown.