Normally-Off MOS-HFET on AlGaN/GaN-on-Si(110) Grown by NH3 MBE

Abstract

Due to the difficulty of GaN epitaxy growth on Si(001) substrate, GaN-on-Si wafers are generally grown on Si(111) substrates. Because of the poor electrical characteristics of Si(111) orientation, monolithic integration between CMOS ICs and GaN devices cannot be implemented on GaN-on-Si(111) wafers. At this point of view, Si(110) substrate will be an alternative choice for GaN-on-Si epitaxy growth, because it has good atomic arrangement with AlN seed layer and an advantage of excellent hole mobility characteristics over Si(001). We have developed high quality GaN epitaxy growth technique on Si(110) substrate using NH3 MBE and demonstrated normally-off AlGaN/GaN-on-Si(110) metal-oxide-semiconductor-heterojunction field-effect transistors with an OFF-state breakdown voltage of 610 V. The fabricated device exhibited promising characteristics comparable with those achieved on conventional GaN-on-Si(111) wafers.