METHOD OF IMPROVING SURFACE MORPHOLOGY OF (Ga,Al,In,B)N THIN FILMS AND DEVICES GROWN ON NONPOLAR OR SEMIPOLAR (Ga,Al,In,B)N SUBSTRATES

Abstract

A method for improving the growth morphology of (Ga,Al,In,B)N thin films on nonpolar or semipolar (Ga,Al,In,B)N substrates, wherein a (Ga,Al,In,B)N thin film is grown directly on a nonpolar or semipolar (Ga,Al,In,B)N substrate or template and a portion of the carrier gas used during growth is comprised of an inert gas. Nonpolar or semipolar nitride LEDs and diode lasers may be grown on the smooth (Ga,Al,In,B)N thin films grown by the present invention.

What is claimed is: 
     
         1 . A method for fabricating a III-nitride film, comprising:
 growing a III-nitride film comprising one or more layers on or above a substrate or template, using a III-nitride composition, a non-polar or semi-polar orientation, one or more thicknesses of the one or more layers, growth conditions, and a crystallographic orientation of the substrate or template, wherein the III-nitride film has a top surface including a non-polar or semi-polar plane having a root mean square surface roughness, as-grown, of less than 0.5 nanometers over an area of at least 100 micrometers squared.   
     
     
         2 . The method of  claim 1 , wherein:
 the growth conditions include carrier gas composition, and   at least a portion of the carrier gas composition is comprised of at least one inert gas selected from N 2 , He, Ne, Ar, Kr, and Xe.   
     
     
         3 . The method of  claim 1 , wherein the III-nitride film is a Gallium Nitride film. 
     
     
         4 . The method of  claim 3 , wherein the substrate is a Gallium Nitride substrate. 
     
     
         5 . The method of  claim 4 , wherein the Gallium Nitride film is a non-polar m-plane Gallium Nitride film having the root mean square surface roughness between 0.134 nanometers and 0.5 nanometers over the area. 
     
     
         6 . The method of  claim 3 , wherein the Gallium Nitride film has a thickness of at least 10 micrometers. 
     
     
         7 . The method of  claim 1 , further comprising:
 growing the III-nitride film by Metal Organic Chemical Vapor Deposition on a nonpolar or semipolar III-nitride substrate or template; and   using a carrier gas during the growing step, wherein at least a portion of the carrier gas during growth of a first Gallium Nitride layer in the nonpolar or semipolar film is comprised of an inert gas, wherein the III-nitride film has a planar top surface having the surface roughness.   
     
     
         8 . The method of  claim 1 , wherein the substrate or template is an m-plane Gallium Nitride substrate, the crystallographic orientation comprises a miscut having a miscut angle toward a [000-1] direction between 0.75° and 1.50°, and the III-nitride film is grown on a surface of the miscut. 
     
     
         9 . The method of  claim 1 , wherein:
 the substrate is a Gallium Nitride substrate;   the III-nitride film includes one or more device layers that emit light having an output power of at least 2 milliwatts at 20 milliamps drive current,   the drive current is direct current, and   the output power is measured through a backside of the Gallium Nitride substrate.   
     
     
         10 . A III-nitride film, comprising:
 one or more layers having a III-nitride composition and a non-polar or semi-polar orientation;   one or more thicknesses of the one or more layers; and   the III-nitride film on or above a crystallographic orientation of a substrate, wherein:
 the III-nitride film has a top surface including a non-polar or semi-polar plane having a root mean square (RMS) surface roughness, as-grown, of less than 0.5 nanometers over an area of at least 100 micrometers squared. 
   
     
     
         11 . The film of  claim 10 , wherein the RMS surface roughness is between on the order of a diameter of Ga,Al,In,B, and N atoms and 0.5 nanometers. 
     
     
         12 . The film of  claim 10 , wherein the RMS surface roughness is between 0.134 nanometers and 0.5 nanometers over the area. 
     
     
         13 . The film of  claim 10 , wherein the RMS surface roughness is between 0.134 nanometers and 0.25 nanometers over the area. 
     
     
         14 . The film of  claim 10 , wherein the RMS surface roughness is less than 0.25 nanometers over the area. 
     
     
         15 . The film of  claim 10 , wherein the film is deposited on a surface of an m-plane Gallium Nitride substrate, and the surface of the m-plane substrate is a miscut with a miscut angle between 0.75° and 1.50° toward a [000-1] direction. 
     
     
         16 . The film of  claim 10 , wherein the film is a Gallium Nitride (GaN) film. 
     
     
         17 . The film of  claim 16 , wherein the substrate is a Gallium Nitride substrate. 
     
     
         18 . The film of  claim 17 , wherein the RMS surface roughness is between 0.134 nanometers and 0.25 nanometers over the area. 
     
     
         19 . The film of  claim 18 , wherein the Gallium Nitride film is a non-polar m-plane Gallium Nitride film. 
     
     
         20 . The film of  claim 19 , wherein the Gallium Nitride film has a thickness of at least 10 micrometers. 
     
     
         21 . The film of  claim 10 , wherein the substrate is a Gallium Nitride substrate. 
     
     
         22 . The film of  claim 10 , wherein:
 the substrate is a Gallium Nitride substrate;   the III-nitride film includes one or more device layers that emit light having an output power including a power of 2 milliwatts, and   the output power is measured through a backside of the Gallium Nitride substrate.