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 for separating a set of III-nitride-based semiconductor layers, comprising:
 separating a set of III-nitride-based semiconductor layers into at least two sets of the III-nitride-based semiconductor layers, the set of III-nitride-based semiconductor layers grown from an opening area, the opening area formed between two growth restrict masks next to each other, the two growth restrict masks formed on a substrate, the set of III-nitride-based semiconductor layers not combined with another set of III-nitride-based semiconductor layers adjacent to the set of III-nitride-based semiconductor layers, the another set of III-nitride-based semiconductor layers grown from another opening area next to the opening area.   
     
     
         2 . The method of  claim 1 , wherein the separating comprises removing a portion of the set of III-nitride-based semiconductor layers in, on, or above the opening area. 
     
     
         3 . The method of  claim 1 , wherein the separating comprises removing the substrate from the at least two sets of III-nitride-based semiconductor layers 
     
     
         4 . The method of  claim 2 , wherein first side surface of one of the at least two sets of the III-nitride-based semiconductor layers faces second side surface of another of the at least two sets of the III-nitride-based semiconductor layers, the another of the at least two sets of the III-nitride-based semiconductor layers adjacent to the one of the at least two sets of the III-nitride-based semiconductor layers, the first side surface and the second side surface appearing after the removing the portion of the set of III-nitride-based semiconductor layers. 
     
     
         5 . The method of  claim 1 , wherein after the removing the substrate, each of the at least two sets of III-nitride-based semiconductor layers is at least a part of a laser device. 
     
     
         6 . The method of  claim 1 , wherein the set of III-nitride-based semiconductor layers are grown by epitaxial lateral overgrowth (ELO). 
     
     
         7 . The method of  claim 6 , wherein the ELO is stopped before the set of III-nitride-based semiconductor layers coalesce with another set of III-nitride-based semiconductor layers, the another set of III-nitride-based semiconductor layers adjacent to the set of III-nitride-based semiconductor layers. 
     
     
         8 . The method of  claim 1 , wherein the removing the substrate comprises separating the set of III-nitride-based semiconductor layers from the substrate completely. 
     
     
         9 . The method of  claim 1 , wherein the substrate is a III-nitride based substrate. 
     
     
         10 . The method of  claim 2 , wherein the removing the portion of the set of III-nitride-based semiconductor layers comprising removing at least a layer bending region from the set of III-nitride-based semiconductor layers along with the set of III-nitride-based semiconductor layers. 
     
     
         11 . The method of  claim 5 , wherein a support substrate is used to remove the substrate. 
     
     
         12 . The method of  claim 11 , wherein the support substrate is divided to form the laser device. 
     
     
         13 . The method of  claim 1 , wherein after the removing the substrate, the substrate is recycled. 
     
     
         14 . The method of  claim 1 , wherein interface between the growth restrict masks and the set of III-nitride semiconductor layers is flat. 
     
     
         15 . The method of  claim 1 , wherein the removing the portion of the set of III-nitride-based semiconductor layers comprises removing at least a part of the growth restrict masks near the portion of the set of III-nitride-based semiconductor layers along with a part of the substrate. 
     
     
         16 . The method of  claim 15 , wherein the part of the substrate is near both the portion of the set of III-nitride-based semiconductor layers and the at least a part of the growth restrict masks. 
     
     
         17 . The method of  claim 1 , wherein the set of III-nitride-based semiconductor layers is separated from another set of III-nitride-based semiconductor layers by non-growth regions, the another set of III-nitride-based semiconductor layers adjacent to the set of III-nitride-based semiconductor layers. 
     
     
         18 . The method of  claim 2 , wherein the at least two sets of the III-nitride-based semiconductor layers are separated by no-growth regions and etching regions, the no-growth regions where the set of III-nitride-based semiconductor layers are not grown on or above the substrate, the etching regions where the portion of set III-nitride-based semiconductor layers is performed is removed. 
     
     
         19 . The method of  claim 10 , wherein the at least a layer bending region includes at least a bended part of the one or more III-nitride-based semiconductor layers. 
     
     
         20 . The method of  claim 10 , wherein the at least a layer bending region is located at an edge of the one or more III-nitride-based semiconductor layers. 
     
     
         21 . The method of  claim 10 , wherein the at least a layer bending region includes at least a bended active region. 
     
     
         22 . The method of  claim 21 , wherein the at least a bended region is at least a bended InGaN/GaN multiple quantum well (MQW) active region.