Investigation on the role of indium in the removal of metallic gallium from soft and hard sputtered GaN (0001) surfaces
2009 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 517, no 21, 6023-6026 p.Article in journal (Refereed) Published
Cleaning of GaN by argon sputtering and subsequent annealing introduces metallic gallium on the GaN surface. Once formed, this metallic gallium can be difficult to remove. it has a strong influence on the Fermi level position in the band gap and poses a problem for subsequent epitaxial growth on the surface. We present a method of removing metallic gallium from moderately damaged GaN surfaces by deposition of indium, and formation of an In-Ga alloy that can be desorbed by annealing at similar to 550 degrees C. After the In-Ga alloy has desorbed, photoemission spectra show that the Ga3d bulk component becomes narrower indicating a smoother and more homogeneous surface. This is also reflected in a sharper low energy electron diffraction pattern. On heavily damaged GaN surfaces, caused by hard sputtering, larger amount of metallic gallium forms after annealing at 600 degrees C. This gallium readily alloys with deposited indium, but the alloy does not desorb until a temperature of 840 degrees C is reached and even then, traces of both indium and metallic gallium could be found on the surface.
Place, publisher, year, edition, pages
2009. Vol. 517, no 21, 6023-6026 p.
Gallium nitride, Surfactant, Cleaning, Indium, Argon sputtering, Surface defects, Photoemission spectroscopy, stoichiometric gan(0001)-1 x-1, core-level photoemission, molecular-beam epitaxy, electron accumulation, ion-bombardment, n-type, deposition, nitride
IdentifiersURN: urn:nbn:se:kth:diva-18636DOI: 10.1016/j.tsf.2009.05.023ISI: 000268438200013ScopusID: 2-s2.0-67449127658OAI: oai:DiVA.org:kth-18636DiVA: diva2:336683
QC 201005252010-08-052010-08-052010-12-10Bibliographically approved