Method of removing a substrate

Abstract

A method of removing a substrate, comprising: forming a growth restrict mask with a plurality of striped opening areas directly or indirectly upon a GaN-based substrate; and growing a plurality of semiconductor layers upon the GaN-based substrate using the growth restrict mask, such that the growth extends in a direction parallel to the striped opening areas of the growth restrict mask, and growth is stopped before the semiconductor layers coalesce, thereby resulting in island-like semiconductor layers. A device is processed for each of the island-like semiconductor layers. Etching is performed until at least a part of the growth restrict mask is exposed. The devices are then bonded to a support substrate. The GaN-based substrate is removed from the devices by a wet etching technique that at least partially dissolves the growth restrict mask. The GaN substrate that is removed then can be recycled.

What is claimed is: 
     
         1 . A method of removing a substrate, comprising:
 removing a portion of a set of one or more III-nitride-based semiconductor layers on or above opening areas, the set of one or more III-nitride-based semiconductor layers grown on a substrate, the opening areas formed between growth restrict masks, the growth restrict masks formed on or above the substrate; and   removing the substrate from the set of one or more III-nitride-based semiconductor layers, wherein after removing the substrate, the set of one or more III-nitride-based semiconductor layers comprises:   at least a layer bending region at an edge of the set of one or more III-nitride-based semiconductor layers, the at least a layer bending region including at least a bended part of the one or more III-nitride-based semiconductor layers; and   at least one etching region at another edge of the set of one or more III-nitride-based semiconductor layers, the at least one etching region separated by etching from another set of one or more III-nitride-based semiconductor layers.   
     
     
         2 . The method of  claim 1 , wherein after removing the substrate, each of the set of the one or more III-nitride-based semiconductor layers is at least a part of a device. 
     
     
         3 . The method of  claim 1 , wherein the set of one or more III-nitride-based semiconductor layers is grown by epitaxial lateral overgrowth (ELO). 
     
     
         4 . The method of  claim 3 , wherein the epitaxial lateral overgrowth is stopped before the set of one or more III-nitride-based semiconductor layers coalesces with another set of III-nitride-based semiconductor layers adjacent to the set of one or more III-nitride-based semiconductor layers. 
     
     
         5 . The method of  claim 1 , wherein the removing the substrate comprises separating the set of one or more III-nitride-based semiconductor layers from the substrate completely. 
     
     
         6 . The method of  claim 1 , wherein the substrate is a III-nitride based substrate. 
     
     
         7 . The method of  claim 2 , wherein a support substrate is used to remove the substrate. 
     
     
         8 . The method of  claim 7 , wherein the support substrate is divided to form the device. 
     
     
         9 . The method of  claim 1 , wherein after the removing the substrate, the substrate is recycled. 
     
     
         10 . The method of  claim 1 , wherein interface between the growth restrict masks and the set of one or more III-nitride semiconductor layers is flat. 
     
     
         11 . The method of  claim 1 , wherein the removing the portion of the set of one or more III-nitride-based semiconductor layers comprises removing a part of the substrate. 
     
     
         12 . The method of  claim 11 , wherein the part of the substrate is near the portion of the set of one or more III-nitride-based semiconductor layers. 
     
     
         13 . The method of  claim 4 , wherein the set of one or more III-nitride-based semiconductor layers is separated from the another set of III-nitride-based semiconductor layers by at least a non-growth region. 
     
     
         14 . The method of  claim 1 , wherein the set of one or more III-nitride-based semiconductor layers is divided into a plurality of island-shaped semiconductor layers after the removing the portion of one or more III-nitride-based semiconductor layers. 
     
     
         15 . The method of  claim 14 , wherein the plurality of island-shaped semiconductor layers are separated by no-growth regions and etching regions, the no-growth regions where the set of one or more III-nitride-based semiconductor layers are not grown on or above the substrate, the etching regions where the portion of the set of one or more III-nitride-based semiconductor layers is removed. 
     
     
         16 . The method of  claim 1 , wherein the at least a bended part includes bended InGaN/GaN multiple quantum well (MQW) active regions. 
     
     
         17 . A device comprising:
 a set of one or more III-nitride-based semiconductor layers, the set of one or more III-nitride-based semiconductor layers including Epitaxial Lateral Overgrowth (ELO) III-nitride-based layers and device layers;   at least a layer bending region at an edge of the set of one or more III-nitride-based semiconductor layers, the at least a layer bending region comprising at least a bended part of the one or more III-nitride-based semiconductor layers; and   at least one etching region at another edge of the set of one or more III-nitride-based semiconductor layers, the at least one etching region separated by etching from another set of one or more III-nitride-based semiconductor layers.   
     
     
         18 . The device of  claim 17 , wherein the at least a bended part is at least a bended InGaN/GaN multiple quantum well (MQW) active region.