HAZDRA, P., et al. Low-resistance ohmic contacts on boron-doped {113} oriented homoepitaxial diamond layers. Diamond and Related Materials. 2022, 121 ISSN 0925-9635. DOI 10.1016/j.diamond.2021.108797.
Refractory metals (titanium, molybdenum, and zirconium) with a gold overlayer were used to form ohmic contacts on {113}-oriented boron doped diamond epitaxial layers (boron concentration ranging from 1019 to 1021 cm−3). Morphology and thickness of deposited layers were determined by AFM and X-SEM; resistivity, carrier concentration and mobility were determined by Hall measurement. Specific contact resistance RCsp of evaporated Ti/Au, Zr/Au, and Mo/Au contacts was measured using c-TLM structures after different annealing stages at temperatures up to 850 °C. Results show that on layers with {113} orientation it is possible to achieve ohmic contacts of comparable quality as for layers with {100} orientation. For all three metal systems, the lowest values for specific contact resistance reached 1 × 10−6 Ω.cm2. Ti/Au contacts show a stable ohmic behavior over the whole range of annealing temperatures, while Mo/Ti contacts had to be annealed above 500 °C to reduce the Schottky barrier and achieve good ohmic contact on lower B doped layers. Zr/Au contacts exhibit the lowest adhesion and required annealing to at least 700 °C to achieve ideal electrical and mechanical properties. Mo/Au and Zr/Au contacts on highly boron doped layers (~1021 cm−3) show excellent contacts when annealed at 700 °C, and therefore can be considered as improved candidates for ohmic contacts for diamond-based high-temperature power electronics than the conventional Ti/Au (Ti/Pt/Au) contact system. In summary, this study confirms the suitability of {113} oriented boron doped diamond epitaxial layers for the fabrication of diamond power electronic devices with excellent ohmic contacts.
eng
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application/pdf
dc.language.iso
eng
dc.publisher
Elsevier Science
dc.relation.ispartof
Diamond and Related Materials
dc.subject
Diamond
eng
dc.subject
Contacts
eng
dc.subject
Boron-doping
eng
dc.subject
Chemical vapor deposition
eng
dc.subject
Contact resistance
eng
dc.title
Low-resistance ohmic contacts on boron-doped {113} oriented homoepitaxial diamond layers