Low-resistance smooth-surface Ti/Al/Cr/Mo/Au n-type Ohmic contact to AlGaN/GaN heterostructures

Yung-Ling Lan; Hung-Cheng Lin; Hsueh-Hsing Liu; Geng-Yen Lee; Fan Ren; Pearton, Stephen J.; Mao-Nan Chang; Jen-Inn Chyi
June 2009
Applied Physics Letters;6/15/2009, Vol. 94 Issue 24, p243502
Academic Journal
A comparative study of the specific contact resistivity and surface morphology of Ti/Al/Ni/Au, Ti/Cr/Mo/Au, and Ti/Al/Cr/Mo/Au metal contact stacks on AlGaN/GaN heterostructures is reported. Compared to the conventional Ti/Al/Ni/Au contact, the Ti/Al/Cr/Mo/Au contact has much smoother surface and achieves minimum specific contact resistivity of 1.1×10-6 Ω cm2. This contact maintains its low contact resistivity after storage at 200 °C for 100 h in N2. The robustness of this contact is attributed to the Cr and Mo layers, which suppress the formation of Al–Au alloys in the contact stack.


Related Articles

  • Carrier transport mechanism of low resistance Ti/Al/Au ohmic contacts to AlInN/GaN heterostructures. Kim, Seongjun; Ryou, Jae-Hyun; Dupuis, Russell D.; Kim, Hyunsoo // Applied Physics Letters;2/4/2013, Vol. 102 Issue 5, p052107 

    The carrier transport mechanism of a low resistance Ti/Al/Au Ohmic contact to AlInN/GaN heterostructures was investigated. The Ohmic contact produced upon thermal annealing was due to the generation of TiN contact inclusions with a density of 2.8 × 108 cm-2, i.e., spike mechanism. The sheet...

  • Ohmic contacts to n+-GaN capped AlGaN/AlN/GaN high electron mobility transistors. Wang, Liang; Mohammed, Fitih M.; Ofuonye, Benedict; Adesida, Ilesanmi // Applied Physics Letters;7/2/2007, Vol. 91 Issue 1, p012113 

    Investigations of Ti/Al/Mo/Au Ohmic contact formation, premetallization plasma treatment effects, and interfacial reactions for n+-GaN capped AlGaN/AlN/GaN heterostructures are presented. Ti thickness played an important role in determining contact performance. Transmission electron microscopy...

  • Differences in the reaction kinetics and contact formation mechanisms of annealed Ti/Al/Mo/Au Ohmic contacts on n-GaN and AlGaN/GaN epilayers. Wang, Liang; Mohammed, Fitih M.; Adesida, Ilesanmi // Journal of Applied Physics;1/1/2007, Vol. 101 Issue 1, p013702 

    Ti/Al-based multilayer metallizations are usually used interchangeably for n-GaN and AlGaN/GaN epilayers. Our investigations show that, although excellent Ohmic performances were obtained on both cases, the reaction pathways/kinetics and Ohmic contact formation mechanisms of Ti/Al/Mo/Au...

  • Influence of metal/n-InAs/interlayer/n-GaAs structure on nonalloyed ohmic contact resistance. Shiraishi, Y.; Furuhata, N.; Okamoto, A. // Journal of Applied Physics;11/1/1994, Vol. 76 Issue 9, p5099 

    Investigates the influence of interlayer structures on nonalloyed ohmic contact resistance, in terms of the crystalline defects and the potential barrier at the interlayer/gallium arsenide (GaAs) interface. Effect of the lattice mismatch between InAs and GaAs on the dependence of the interlayer...

  • The mechanism of current flow in an alloyed In-GaN ohmic contact. Blank, T.; Gol'dberg, Yu.; Konstantinov, O.; Nikitin, V.; Posse, E. // Semiconductors;Oct2006, Vol. 40 Issue 10, p1173 

    The resistance of alloyed In-GaN ohmic contact is studied experimentally. In the temperature range 180–320 K, the resistance per unit area increases with temperature, which is typical of metallic conduction and disagrees with current flow mechanisms associated with thermionic,...

  • Thermally driven defect formation and blocking layers at metal-ZnO interfaces. Mosbacker, H. L.; Zgrabik, C.; Hetzer, M. J.; Swain, A.; Look, D. C.; Cantwell, G.; Zhang, J.; Song, J. J.; Brillson, L. J. // Applied Physics Letters;8/13/2007, Vol. 91 Issue 7, p072102 

    The authors used depth-resolved cathodoluminescence spectroscopy and current-voltage measurements to probe the temperature-dependent formation of native point defects and reaction layers at metal-ZnO interfaces and their effect on transport properties. These results identify characteristic...

  • Comment on “Contact mechanisms and design principles for alloyed Ohmic contacts to n-GaN” [J. Appl. Phys. 95, 7940 (2004)]. Yow-Jon Lin // Journal of Applied Physics;10/1/2006, Vol. 100 Issue 7, p073707 

    The contact mechanism and design principles for alloyed Ohmic contacts to n-GaN were investigated in Mohammad’s paper [J. Appl. Phys. 95, 7940 (2004)]. Mohammad’s study demonstrated that both tunneling and thermionic emission were equally important for low resistivity at the...

  • Formation mechanism of Ohmic contacts on AlGaN/GaN heterostructure: Electrical and microstructural characterizations. Wang, Liang; Mohammed, Fitih M.; Adesida, Ilesanmi // Journal of Applied Physics;May2008, Vol. 103 Issue 9, p093516 

    The electrical characteristics and interfacial reactions of Ti/Al/Mo/Au metallization on AlGaN/GaN heterostructures at various annealing temperatures ranging from 400 to 950 °C have been investigated in an effort to elucidate the Ohmic contact formation mechanism. A transition from Schottky...

  • V/Al/V/Ag Ohmic contacts to n-AlGaN/GaN heterostructures with a thin GaN cap. Miller, M. A.; Mohney, S. E. // Applied Physics Letters;7/2/2007, Vol. 91 Issue 1, p012103 

    Silver is studied as a replacement for Au in V- and Ti-based Ohmic contacts to GaN-capped n-Al0.27Ga0.73N/GaN heterostructures for high electron mobility transistors. An optimized V/Al/V/Ag contact provided a low contact resistance of 0.27 Ω mm and specific contact resistance of 1.7×10-6...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics