Study of structure and surface morphology of two-layer contact Ti/Al metallization
| Autor: | N. I. Kargin, R. V. Zakharchenko, Mikhail V. Pashkov, Kirill D. Vanyukhin, Lev A. Seidman |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Annealing (metallurgy) Electron beam deposition method Two layer Intermetallic chemistry.chemical_element lcsh:TK7800-8360 02 engineering and technology 01 natural sciences Contact metallizations GaN Aluminium 0103 physical sciences Thermal annealing of metallization Wafer Ohmic contact Sheet resistance Ohmic contacts Titanium-aluminum metallization 010302 applied physics Metallurgy lcsh:Electronics General Medicine 021001 nanoscience & nanotechnology Isotropic etching chemistry 0210 nano-technology |
| Zdroj: | Modern Electronic Materials, Vol 2, Iss 2, Pp 54-59 (2016) |
| ISSN: | 2452-1779 |
| DOI: | 10.1016/j.moem.2016.09.005 |
| Popis: | Ti/Al/Ni/Au metallization widely used in the technology of GaN base devices have a very important imperfection i.e. rough surface. There are different opinions about the causes of this imperfection: balling-up of molten aluminum or the appearance of intermetallic melt phases in the Au–Al system. To check the effect of the former cause, we have studied the formation of rough surface after annealing of Ti/Al metallization which is used as a basis of many metallization systems for GaN. The substrates were made from silicon wafers covered with Si3N4 films (0.15 μm). On these substrates we deposited the Ti(12 nm)/Al(135 nm) metallization system. After the deposition the substrates were annealed in nitrogen for 30 s at 850 °С. The as-annealed specimens were tested for metallization sheet resistivity, appearance and surface morphology. We have shown that during annealing of the Ti/Al metallization system, mutual diffusion of the metals and their active interaction with the formation of intermetallic phases occur. This makes the metallization system more resistant to subsequent annealing, oxidation and chemical etching. After annealing the surface of the Ti/Al metallization system becomes gently matted. However, large hemispherical convex areas (as in the Ti/Al/Ni/Au metallization system) do not form. Thus, the hypothesis on the balling-up of molten aluminum on the surface of the Ti/Al metallization system has not been confirmed. |
| Databáze: | OpenAIRE |
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