Title :
TEM/HREM of Ti/Al and WNi/Ti/Al ohmic contacts for n-AlGaN
Author :
Ruvimov, S. ; Liliental-Weber, Z. ; Washburn, J. ; Qiao, D. ; Lui, Q.Z. ; Lau, S.S.
Author_Institution :
Lawrence Berkeley Lab., CA, USA
Abstract :
High resolution and analytical transmission electron microscopy was applied to characterize the microstructure of Al/Ti and W/Al/Ti ohmic contacts to AlGaN/GaN HFET structures. Formation of a 15-25 nm thick interfacial AlTi2N layer appears to be essential for ohmic contract behavior indicating a tunneling contact mechanism. Contact resistance was found to depend on the structure and composition of the metal and AlGaN layers, and on atomic structure of the interface. Contact resistivity increases with Al fraction in the AlGaN layer
Keywords :
III-V semiconductors; aluminium; aluminium compounds; contact resistance; field effect transistors; gallium compounds; interface structure; nickel alloys; ohmic contacts; semiconductor-metal boundaries; titanium; transmission electron microscopy; tungsten alloys; tunnelling; Al fraction; HFET; HREM; TEM; WNi-Ti-Al-AlGaN; contact resistance; interface atomic structure; interfacial AlTi2N layer; microstructure; ohmic contacts; tunneling contact mechanism; Aluminum gallium nitride; Contact resistance; Contracts; Gallium nitride; HEMTs; MODFETs; Microstructure; Ohmic contacts; Transmission electron microscopy; Tunneling;
Conference_Titel :
Semiconducting and Insulating Materials, 1998. (SIMC-X) Proceedings of the 10th Conference on
Conference_Location :
Berkeley, CA
Print_ISBN :
0-7803-4354-9
DOI :
10.1109/SIM.1998.785117
