Impact of rapid thermal annealing on Mg‐implanted GaN with a SiOx/AlN cap‐layer

Local p‐type doping in GaN is a key issue for device development but it remains a challenge to be achieved. In this work, we studied the activation of Mg implanted in the GaN. Multi‐energy implantations were performed to achieve a “box‐like” profile. SIMS measurements showed unexpected deep Mg profi...

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Bibliographic Details
Published in:Physica status solidi. A, Applications and materials science Applications and materials science, 2017-04, Vol.214 (4), p.n/a
Main Authors: Khalfaoui, Wahid, Oheix, Thomas, El‐Zammar, Georgio, Benoit, Roland, Cayrel, Frederic, Faulques, Eric, Massuyeau, Florian, Yvon, Arnaud, Collard, Emmanuel, Alquier, Daniel
Format: Article
Language:English
Subjects:
Activation analysis
Activation energy
AlN
Aluminum gallium nitrides
Aluminum nitride
Annealing
Capping
Channeling
Depth profiling
Doping
Etching
Gallium nitrides
GaN
Implantation
ion implantation
Junction diodes
magnesium
P-n junctions
rapid thermal annealing
Schottky diodes
silicon oxide
Sputtering
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Summary:Local p‐type doping in GaN is a key issue for device development but it remains a challenge to be achieved. In this work, we studied the activation of Mg implanted in the GaN. Multi‐energy implantations were performed to achieve a “box‐like” profile. SIMS measurements showed unexpected deep Mg profile due to defect‐assisted channeling in the GaN. In addition, a high‐density defect region induced by the implantation was evidenced by TEM characterization. To protect the GaN surface prior to high temperature annealing, an AlN cap‐layer was deposited by reactive sputtering followed by SiOx deposition leading to a double cap‐layer. Afterwards, the capped samples were RTA‐annealed at high temperatures for several minutes under nitrogen. Two types of annealing processes were applied: a monocycle and a multicycle annealing. After annealing, the double cap‐layer was etched using chemical solutions. AFM characterizations, after annealing and cap‐layer etching, demonstrated that a GaN surface with similar roughness to as‐grown samples and pit‐free can be achieved after both monocycle and multicycle annealing steps. However, an AlGaN layer at the AlN/GaN interface is observed by ToF‐SIMS and remained after the etching of the AlN layer. Finally, Schottky diodes were processed on the unimplanted and annealed samples, evidencing a double barrier, while P/N junction diodes are still being processed on the implanted and annealed samples.
ISSN:1862-6300
1862-6319
DOI:10.1002/pssa.201600438