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Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.42 [2004] >
IJPAP Vol.42(05) [May 2004] >
| Title: | Interfacial reaction and surface morphology of Pd/Re contact schemes to p-type GaN |
| Authors: | Reddy, V Rajagopal
Ramesh, C K
Reddy, P Narasimha |
| Keywords: | interfacial reaction
Pd/Re contacts
surface morphology
glancing angle XRD
Auger depth profiling |
| Issue Date: | May-2004 |
| Publisher: | CSIR |
| IPC Code: | H 01 C 10/00 |
| Abstract: | The interfacial reactions between the
Pd (20 nm) / Re (25 nm) contacts and p-GaN(1.13×1017cm-3) have been investigated using glancing
angle XRD and Auger depth profiling. The samples are annealed at temperatures
of 550 ºC and 650 ºC for 1 min in a nitrogen ambient. The I-V measurements show
that the as-deposited sample is ohmic with a contact resistance of 1.4×10-3
Ω
cm2. However, the annealing of the sample at 550 ºC results in much
better ohmic behaviour with a specific contact resistance of 8.7×10-4
Ω
cm2. Further, increase in annealing temperature (650 ºC) causes the
degradation of the ohmic property. Based on AES and XRD results, the formation
of Ga-Pd reaction phases results in the generation of Ga vacancies at the GaN
surface region, which plays a role
in reducing contact resistivity. The AFM results show that the surface morphology of the as-deposited contact is
fairly smooth (with a rms roughness of 1.7 nm) and when annealed at 550 °C,
contact has become somewhat degraded with a root-mean-square roughness of 6.5
nm. |
| Page(s): | 361-365 |
| ISSN: | 0975-1041 (Online); 0019-5596 (Print) |
| Source: | IJPAP Vol.42(05) [May 2004]
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