Electrical properties and microstructure of V/Al/Ni/Au contacts on n-Al0.65Ga0.35N:Si with different Au thicknesses and annealing temperatures. (1st October 2022)

• Record Type: Journal Article
• Authors: Cho, H K; Mogilatenko, A; Susilo, N; Ostermay, I; Seifert, S; Wernicke, T; Kneissl, M; Einfeldt, S
• Is Part Of: Semiconductor science and technology. Volume 37:Number 10(2022)
• Publication Date: 2022-10-01
• Subjects: ohmic contact -- n-AlGaN -- high Al mole fraction -- UV LED -- Au rich phase -- AlN; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1361-6641/ac8e8f
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: We investigated the formation of ohmic contacts as a result of intermetallic phase formation between V, Al, Ni, and Au in V/Al/Ni/Au metal stacks on n-Al0.65 Ga0.35 N:Si. In particular, the influence of Au metal thickness and annealing temperature was analysed. The lowest annealing temperature of 750 °C for an ohmic contact with a smooth surface and a contact resistivity of about 2.4 × 10 −5 Ωcm 2 was achieved for V(15 nm)/Al(120 nm)/Ni(20 nm)/Au(40 nm). The lowest contact resistivity is accompanied by formation of two thin interfacial regions consisting of AlN and an Au-rich phase. We suggest that not only the formation of thin interfacial AlN layer is important for a low contact resistance, but also the formation of the Au-rich interface can have a favourable effect on the contact properties.