Growth and characterization of crack-free AlGaN on AlN interlayer

The AlGaN samples have been grown on AlN interlayer (IL) by metalorganic vapor phase epitaxy (MOVPE). The effects of AlN IL on improvement of crystalline quality of AlGaN and Al incorporation efficiency were investigated. The samples were characterized by X-ray diffraction (XRD) using synchrotron radiation and MeV He ion Rutherford backscattering spectrometry (RBS). AlN IL shows a role of suppre ssing edge dislocation defect but bring an increase in the density of screw dislocation. the AlN IL also resulted in a change in the state of stress in AlGaN from tension to compression. Crack-free AlGaN films were grown successfully by inserting two AlN IL.