P-contact layer for a III-P semiconductor light emitting device
View Patent ↗A device includes a semiconductor structure with at least one III-P light emitting layer disposed between an n-type region and a p-type region. The semiconductor structure further includes a GaAs x P 1−x p-contact layer, wherein x<0.45. A first metal contact is in direct contact with the GaAs x P 1−x p-contact layer. A second metal contact is electrically connected to the n-type region. The first and second metal contacts are formed on a same side of the semiconductor structure.
1. A device comprising:
a semiconductor structure comprising:
at least one III-P light emitting layer disposed between an n-type region and a p-type region;
a GaAs x P 1−x p-contact layer, wherein x<0.45;
a first metal contact in direct contact with the GaAs x P 1−x p-contact layer; and
a second metal contact electrically connected to the n-type region;
wherein the first and second metal contacts are formed on a same side of the semiconductor structure.
2. The device of claim 1 wherein the GaAs x P 1−x p-contact layer has a constant composition x.
3. The device of claim 2 wherein 0.2<x<0.4.
4. The device of claim 1 wherein the GaAs x P 1−x p-contact layer has a graded composition x.
5. The device of claim 1 wherein the GaAs x P 1−x p-contact layer has a composition graded from x=0 to x<0.45.
6. The device of claim 1 wherein the first metal contact comprises:
a mirror; and
a plurality of Ohmic contact regions disposed between the mirror and the GaAs x P 1−x p-contact layer.
7. The device of claim 6 wherein the mirror comprises silver and the plurality of Ohmic contact regions comprise one of AuZn and Al.
8. The device of claim 1 wherein the p-type region comprises:
a cladding layer in direct contact to the light emitting layer; and
a region with a graded composition disposed between the cladding layer and the contact layer.
9. The device of claim 8 wherein:
the cladding layer comprises Al 0.48 In 0.52 P; and
the region with graded composition is graded from AlInP to (Al 0.3 Ga 0.7 ) 0.47 In 0.53 P.
10. A method comprising:
growing on a growth substrate a semiconductor structure comprising:
at least one III-P light emitting layer disposed between an n-type region and a p-type region; and
a GaAs x P 1−x p-contact layer, wherein x<0.45;
forming a first metal contact in direct contact with the GaAs x P 1−x p-contact layer;
etching away a portion of the at least one III-P light emitting layer and the p-type region to expose a portion of the n-type region; and
forming a second metal contact electrically connected to the n-type region;
wherein the first and second metal contacts are formed on a same side of the semiconductor structure.
11. The method of claim 10 wherein growing a semiconductor structure comprises growing the p-contact layer using tetrabutylarsine (TBAs) as an arsine source.
12. The method of claim 10 wherein growing a semiconductor structure comprises growing the p-contact layer using tetrabutylphosphine (TBP) as a phosphine source.
13. The method of claim 10 further comprising removing the growth substrate.