Method for removal of devices using a trench
An epitaxial lateral overgrowth (ELO) layer is grown on an opening area of a substrate, wherein the ELO layer is higher than a surface 5 of a trench in the substrate. The trench is apt to form a symmetric shape of the ELO layer, which renders it suitable for flip-chip bonding The shape of the ELO layer has a depressed surface region at a back side of a bar formed by the ELO layer. A cleaving point is located higher than the bottom of the ELO layer, so that a force can be efficiently applied to 10 the cleaving point for removing the bar.
1. A method, comprising:
etching a substrate toform one or more trenches on a surface of the substrate;
depositing a growth restrict mask on or above the substrate, including at least partially on or in the trenches, wherein the growth restrict mask has one or more opening areas where the surface of the substrate is exposed;
growing one or more III-nitride epitaxial lateral overgrowth (ELO) layers on the surface of the substrate at the opening areas of the growth restrict mask, wherein the III-nitride ELO layers have a depressed separate region formed by the trenches in the substrate;
growing one or more III-nitride semiconductor device layers on the III-nitride ELO layers to create one or more island-like III-nitride semiconductor layers on which one or more opto-electronic devices are fabricated;
removing the growth restrict mask, and
then removing the opto-electronic devices from the substrate.
2. The method of claim 1 , wherein the growth restrict mask deposited in the trenches has one or more of the opening areas in the trenches.
3. The method of claim 2 , wherein the III-nitride ELO layers are grown at the opening areas in the trenches.
4. The method of claim 1 , wherein the etching of the substrate to form the trenches on the surface of the substrate results in one or more remaining surface regions of the substrate.
5. The method of claim 4 , wherein the growth restrict mask is deposited on at least a portion of the remaining surface regions.
6. The method of claim 5 , wherein the portion of the remaining surface regions comprises an edge of the remaining surface regions.
7. The method of claim 5 , wherein the growth restrict mask deposited on the portion of the remaining surface regions determines where cleaving should start to remove the devices from the substrate.
8. The method of claim 1 , wherein the III-nitride ELO layers are grown from the opening areas of the growth restrict mask without coalescing, leaving no-growth regions between separate islands of the III-nitride ELO layers.
9. The method of claim 8 , wherein the trenches result in a symmetric shape for the separate islands of the III-nitride ELO layers, and the symmetric shape for the separate islands of the III-nitride ELO layers results in the devices being suitable for flip-chip bonding.
10. The method of claim 1 , wherein a surface of the depressed separate regions is higher than a bottom of the III-nitride ELO layers.
11. The method of claim 10 , wherein one or more cleaving points are located higher than the bottom of the III-nitride ELO layers, such that a force is applied to the cleaving points for removal of the devices from the substrate.