Method for improving epitaxy quality (surface irregularities and defect density) of aluminum nitride, indium, gallium ((Al, In, Ga) N) freestanding substrates for optoelectronic devices and electronic devices

For example, a III-V nitride homoepitaxial microelectronic device structure is described that includes a III-V nitride homoepitaxial epilayer on a freestanding III-V nitride substrate. Using a Group III source material and a nitrogen source material, the V / III ratio is in the range of about 1 to about 105, the nitrogen source material partial pressure is in the range of about 1 to about 103 Torr, and the growth temperature is in the range of about 500 to about 1250 ° C. Depositing a group III-V nitride homoepitaxial layer with a VPE method under process conditions with growth rates ranging from about 0.1 microns / hour to about 500 microns / hour to provide the corresponding group III-V nitride Various processing techniques have been disclosed, including methods for forming a III-V nitride homoepitaxial layer on a substrate. III-V nitride homoepitaxial microelectronic device structures can be usefully used for device applications such as UV LEDs and high electron transfer transistors.