Pre-cutting a back side of a silicon substrate for growing better iii-v group compound layer on a front side of the substrate

Abstract

The present disclosure involves an apparatus. The apparatus includes a substrate having a front side a back side opposite the front side. The substrate includes a plurality of openings formed from the back side of the substrate. The openings collectively define a pattern on the back side of the substrate from a planar view. In some embodiments, the substrate is a silicon substrate or a silicon carbide substrate. Portions of the silicon substrate vertically aligned with the openings have vertical dimensions that vary from about 100 microns to about 300 microns. A III-V group compound layer is formed over the front side of the silicon substrate. The III-V group compound layer is a component of one of: a light-emitting diode (LED), a laser diode (LD), and a high-electron mobility transistor (HEMT).

What is claimed is: 
     
         1 . A method, comprising:
 forming a plurality of recesses on a first surface of a substrate, the substrate being a silicon substrate or a silicon carbide substrate; and   thereafter forming one or more III-V group compound layers over a second surface of the substrate, the first surface and the second surface being opposite one another.   
     
     
         2 . The method of  claim 1 , further comprising: forming a lattice-buffer layer over the second surface of the substrate, the lattice-buffer layer containing a material that reduces a lattice mismatch between a III-V group compound material and silicon or silicon carbide, wherein the one or more III-V group compound layers are formed over the lattice-buffer layer. 
     
     
         3 . The method of  claim 1 , further comprising: forming one of a light-emitting diode (LED), a laser diode (LD), or a high-electron mobility transistor (HEMT) over the second surface of the substrate, wherein the III-V group compound layers are components of the LED, the LD, or the HEMT. 
     
     
         4 . The method of  claim 1 , wherein the forming of the recesses comprises performing an etching process or a laser cutting process to the first surface of the substrate. 
     
     
         5 . The method of  claim 1 , wherein the recesses collectively define one of the following patterns in a planar view: a crisscrossing rectangles pattern, a crisscrossing triangles pattern, a concentric circles pattern, a multiple-holes pattern, a multiple-rods pattern, and a radial pattern. 
     
     
         6 . The method of  claim 1 , wherein the recesses are formed to each have sidewalls and a bottom surface. 
     
     
         7 . The method of  claim 1 , wherein the recesses are formed to be substantially identical to one another. 
     
     
         8 . The method of  claim 1 , wherein the recesses are formed to each have a lateral dimension in a range from about 10 microns to about 100 microns. 
     
     
         9 . The method of  claim 1 , wherein portions of the substrate aligned with the recesses have a thickness range between about 100 microns and about 300 microns. 
     
     
         10 . The method of  claim 1 , further comprising: before the forming of the one or more III-V group compound layers:
 boiling the substrate in a sulfuric acid (H 2 SO 4 :H 2 O 2 ) solution; and   thereafter dipping the substrate in a hydrofluoric acid (HF) solution.   
     
     
         11 . A method, comprising:
 forming, via an etching process or a laser cutting process, a plurality of trenches on a back surface of a substrate, the substrate being a silicon substrate or a silicon carbide substrate;   thereafter growing a lattice-buffer layer over the front surface of the substrate, the lattice-buffer layer containing a material that reduces a lattice mismatch between a III-V group compound material and silicon or silicon carbide;   thereafter forming a light-emitting diode (LED), a laser diode (LD), or a high-electron mobility transistor (HEMT) over the lattice buffer layer, wherein the forming of the LED, the LD, or the HEMT includes growing a III-V group compound layer over the lattice-buffer layer.   
     
     
         12 . The method of  claim 11 , wherein the forming of the trenches is performed such that the trenches collectively define one of the following patterns in a bottom view: a crisscrossing rectangles pattern, a crisscrossing triangles pattern, a concentric circles pattern, a multiple-holes pattern, a multiple-rods pattern, and a radial pattern. 
     
     
         13 . The method of  claim 11 , wherein the forming of the trenches is performed such that:
 the trenches each have sidewall surfaces and a bottom surface; and   the trenches have substantially identical shapes and sizes.   
     
     
         14 . The method of  claim 11 , further comprising: before the forming of the lattice-buffer layer:
 boiling the substrate in a sulfuric acid (H 2 SO 4 :H 2 O 2 ) solution; and   thereafter dipping the substrate in a hydrofluoric acid (HF) solution.   
     
     
         15 . A method of growing a III-V group compound material on a substrate, the method comprising:
 forming a plurality of openings in a back side of a substrate, wherein the openings collectively define a pattern on the back side of the substrate from a planar view; and   thereafter growing a III-V group compound layer over a front side of the substrate in an epitaxial process.   
     
     
         16 . The method of  claim 15 , further comprising: forming one of: a light-emitting diode (LED), a laser diode (LD), and a high-electron mobility transistor (HEMT) over the front side of the substrate, wherein the III-V group compound layer is a part of one of: the LED, the LD, and the HEMT. 
     
     
         17 . The method of  claim 15 , wherein the substrate is a silicon substrate, and wherein the growing the III-V group compound layer is performed so that the III-V group compound layer epitaxially grown directly on the front side of the silicon substrate. 
     
     
         18 . The method of  claim 17 , further comprising, before the growing the III-V group compound layer:
 boiling the silicon substrate in a sulfuric acid (H 2 SO 4 :H 2 O 2 ) solution; and   thereafter dipping the silicon substrate in a hydrofluoric acid (HF) solution.   
     
     
         19 . The method of  claim 15 , wherein the forming the plurality of openings comprises etching or laser cutting the openings into the substrate in a manner such that a thickness of a remaining portion of the substrate having no openings is in a range from about 100 microns to about 300 microns, and a lateral dimension of each of the openings is in a range from about 10 microns to about 100 microns. 
     
     
         20 . The method of  claim 15 , wherein the pattern includes one of: a crisscrossing rectangles pattern, a crisscrossing triangles pattern, a concentric circles pattern, a multiple-holes pattern, a multiple-rods pattern, and a radial pattern.