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Microanalysis of the Ti/Al and Ti/Al/Mo/Au ohmic contacts metallization to AlGaN/GaN heterostructures
Author(s) -
Macherzyński Wojciech,
Stafiniak Andrzej,
Paszkiewicz Bogdan,
Gryglewicz Jacek,
Paszkiewicz Regina
Publication year - 2016
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532684
Subject(s) - ohmic contact , materials science , annealing (glass) , heterojunction , sheet resistance , contact resistance , metallurgy , optoelectronics , composite material , layer (electronics)
The article presents the comparative study of two metallization schemes, Ti/Al bilayer and Ti/Al/Mo/Au multilayer to AlGaN/GaN heterostructures. The influence of thermal annealing on the topography and sheet resistance R sh of the metallization was investigated. At the temperature of annealing up to 805 °C Ti/Al metallization morphology changed but the metallization continuity was sufficient to obtain the sheet resistance below 2 Ω/□. Annealing at 820 °C caused the strong increase of sheet resistance up to 254 Ω/□. These results clearly indicated on very large heterogeneity of Ti/Al layers, material phase segregation, and the separation into individual islands. The annealing of Ti/Al/Mo/Au metallization also resulted in rise of sheet resistance. But the continuity of Ti/Al/Mo/Au layers did not deteriorate the sheet resistance value and homogeneity so significantly as for Ti/Al layers. In this case the changes were much lower, R sh increased only to 1.15 Ω/□.