A1InGaP LED having reduced temperature dependence
View Patent ↗To increase the lattice constant of AlInGaP LED layers to greater than the lattice constant of GaAs for reduced temperature sensitivity, an engineered growth layer is formed over a substrate, where the growth layer has a lattice constant equal to or approximately equal to that of the desired AlInGaP layers. In one embodiment, a graded InGaAs or InGaP layer is grown over a GaAs substrate. The amount of indium is increased during growth of the layer such that the final lattice constant is equal to that of the desired AlInGaP active layer. In another embodiment, a very thin InGaP, InGaAs, or AlInGaP layer is grown on a GaAs substrate, where the InGaP, InGaAs, or AlInGaP layer is strained (compressed). The InGaP, InGaAs, or AlInGaP thin layer is then delaminated from the GaAs and relaxed, causing the lattice constant of the thin layer to increase to the lattice constant of the desired overlying AlInGaP LED layers. The LED layers are then grown over the thin InGaP, InGaAs, or AlInGaP layer.
1. A method comprising:
providing a substrate comprising;
a host; and
a III–V seed layer banded to the host, wherein the III–V seed layer comprises at least three elements from group III and group V; and
growing a plurality of III–V layers on the seed layer.
2. The method of claim 1 wherein the substrate further comprises a bonding layer disposed between the host and the III–V seed layer.
3. The method of claim 1 wherein a lattice constant of the III–V seed layer matches a lattice constant of at least one of the plurality of III–V layers grown on the seed layer.
4. The method of claim 1 wherein the seed layer is a III-nitride layer.
5. The method of claim 1 wherein providing a compound substrate comprises:
growing the III–V seed layer on a growth substrate, wherein the III–V seed layer is strained;
bonding the strained III–V layer to the host; and
removing the growth substrate;
wherein the III–V layer at least partially relaxes when the growth substrate is removed.