Interface analysis of Ti/Al/Ti/Au ohmic contacts with regrown n⁺‐GaN layers using molecular beam epitaxy

Abstract

The regrowth technique of highly doped n-type GaN layers is reliable and effective for lowering the ohmic contact resistance. The interface between metal contacts with Ti/Al/Ti/Au and regrown n + -GaN/GaN layers were analyzed in detail with transmission electron microscopy.

Analysis of AlGaN/GaN high electron mobility transistors with nonalloyed Ohmic contacts achieved by selective area growth using plasma assisted molecular beam epitaxy

“…Our technique was also shown to be more effective than ion implantation to improve the Ohmic contact properties [16,17]. In this work, the detailed study of the interface between nonalloyed contact metals and the regrown GaN is performed and compared with the conventional alloyed counterpart using X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), Auger electron microscopy (AES) and scanning electron microscopy (SEM).…”

High‐current AlGaN/GaN high electron mobility transistors achieved by selective‐area growth via plasma‐assisted molecular beam epitaxy

“…In our previous studies, we were able to realize SAG by PAMBE, achieving a record low contact resistivity of 1.8 Â 10 À8 V cm 2 and much enhanced peak drain currents for both GaN MESFET and HEMT [9,10]. We also demonstrated that unlike ion implantation, the damage-free PAMBE-SAG technique is able to suppress the buffer leakage current and improve the breakdown characteristics [11][12][13]. Due to the simultaneous improvement of drain current and breakdown voltage, PAMBE-SAG is most suited to fabricate high power transistors.…”