Growing N-polar III-nitride Structures
Methods of forming a stable N-polar III-nitride structure are described. A Ga-polar device can be formed on a substrate. A carrier wafer is attached to the Ga-polar surface. The substrate is removed from the assembly. The N-polar surface that remains is offcut and, optionally, subsequent layers are formed on the offcut surface.
1 . A method of forming an N-polar III-nitride structure, comprising:
forming a III-nitride layer on substrate, wherein the III-nitride layer has a Ga-polar face;
bonding a carrier wafer to the Ga-polar face to from an assembly;
removing the substrate from the assembly; and
forming an off-angle exposed surface of the assembly to form the N-polar III-nitride structure.
2 . The method of claim 1 , further comprising implanting the III-nitride layer with hydrogen atoms, wherein removing the substrate from the assembly is performed along a location in which the hydrogen atoms are implanted.
3 . The method of claim 2 , wherein the removing comprises annealing the assembly.
4 . The method of claim 2 , wherein implanting comprises implanting at an angle of about 7°.
5 . The method of claim 1 , wherein forming an off-angle exposed surface comprises polishing.
6 . The method of claim 1 , wherein removing comprises one of ablation or etching.
7 . The method of claim 1 , wherein removing comprises removing a portion of the III-nitride layer.
8 . The method of claim 1 , wherein forming an off-angle exposed surface includes forming an off-angle towards the M-plane at an angle of 10° or less.
9 . The method of claim 1 , wherein forming an off-angle exposed surface includes forming an off-angle towards the A-plane at an angle of 10° or less.
10 . The method of claim 1 , wherein forming a III-nitride layer includes forming the III-nitride layer on a transition layer on the substrate.
11 . The method of claim 1 , further comprising epitaxially growing a GaN based device on the N-polar III-nitride structure.
12 . The method of claim 10 , wherein the GaN based device is a GaN HEMT.
13 . The method of claim 10 , wherein the GaN based device is an LED.
14 . The method of claim 10 , wherein the GaN based device is a laser diode.
15 . The method of claim 10 , wherein the GaN based device is a solar cell.