Research on epitaxial of 250 nm high quality GaN HEMT based on AlN surface leveling technology

Abstract

GaN HEMT epitaxial materials with different buffer layer thicknesses were grown on 4H-SiC substrates by metal-organic chemical vapor deposition (MOCVD). The interface quality between AlN and GaN was improved based on AlN surface planarization technology. A high quality 250 nm thick GaN epitaxial layer was grown. The (0 0 2) plane and the (1 0 2) plane rocking curve have a full width at half maximum of 81 arc seconds and 209 arc seconds, respectively, and the electron mobility of the heterojunction two-dimensional electron gas reaches 2238 cm2/V·s. The surface topography and electrical properties of the material were measured by atomic force microscopy (AFM) and non-contact Hall tester. It was found that the surface smoothness of the GaN buffer layer and the electron mobility of 2DEG did not change significantly, and the X-rays diffractometer was used to analyze the crystal quality and stress of the GaN epitaxial layer.