Electronic Resource
[S.l.]
:
American Institute of Physics (AIP)
Journal of Applied Physics
88 (2000), S. 6364-6368
ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Detailed structure of the interfacial layers of Ti/Ta/Al ohmic contacts to n-type AlGaN/GaN/sapphire are investigated by means of transmission electron microscopy. High-resolution electron microscopy (HREM), optical diffractograms, and computer simulations confirmed that TiN (∼10.0 nm) and Ti3AlN (∼1.4 nm) interfacial layers form at the interface between the Ti layer and the Al0.35Ga0.65N substrate by a solid state reaction during annealing for 3 min in N2 at 950 °C. The orientation relationship between Ti3AlN and Al0.35Ga0.65N was found to be: [011]Ti3AlN(parallel)[21¯1¯0]Al0.35Ga0.65N and (11¯1)Ti3AlN(parallel)(0001)Al0.35Ga0.65N. The cubic Ti3AlN interfacial layer has a lattice parameter of 0.411±0.003 nm with the space group Pm3m matching that of Al0.35Ga0.65N. A model of the atomic configurations of the Ti3AlN/Al0.35Ga0.65N interface is proposed. This model is supported by a good match between the simulated and the experimental HREM image of the Ti3AlN/Al0.35Ga0.65N interface. The formation of TiN and Ti3AlN interfacial layers appears to be responsible for the onset of the ohmic contact behavior in Ti/Ta/Al contacts. © 2000 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1323517
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