[16a-A21-1~12] 15.4 III-V-group nitride crystals

[16a-A21-6] Formation of conductive AlN buffer layer toward vertical high power AlGaN FET on Si substrate

〇Noriko Kurose¹, Yoshinobu Aoyagi¹, Kota Ozeki², Tusutomu Araki² (1.Ritsumeikan Univ. Res. Org. Sci. Technol., 2.Ritsumeikan Univ. Fac. Sci. Technol.)

Keywords:AlN, Si substrate, vertical FET

Conductive AlN epitaxial layer is successfully realized by forming nano size via hole cluster inside AlN buffer layer on a Si substrate. The cluster is found to be originated from formation of Al-Si alloy on a surface of the Si substrate, on which small amount of Al has fed, and recrystallization of Si inside the Al-Si alloy occurs. The cluster filled by conductive n-AlGaN by successive epitaxial growth of AlGaN makes insulating AlN buffer layer to be conductive. The vertical conductivity through AlN is enhanced about 200 times by introducing the nano via holes cluster filled by conductive n-AlGaN. In addition to this formation of conductive AlN, spontaneous voids are formed in the AlGaN grown on the AlN and these voids suppress the clack formation in AlGaN epitaxial layer due to stress relaxation.