Previous study showed that the reactive ion beam (RIB) pretreatment of sapphire prior to GaN deposition results in the reduction of dislocation density in GaN film. Also there was an amorphous phase remaining at the interface region after the GaN deposition at high temperature. Postannealing process was employed to see the structural change due to the recrystallization of the remaining amorphous phase, and the postannealing effect on electrical property of the GaN thin film on RIB treated sapphire (0001) substrate. FWHM of DCXRD spectra and hall mobility of the specimen showed the variation with the various postannealing time at 1000 °C in N2 atmosphere. For the postannealed specimen, FWHM of DCXRD reduced about 50arc-sec and the mobility increased about 80 cm2/V sec. The postannealed specimen with the best mobility was compared with not annealed sample by TEM and observe the decrease of lattice strain and reduction of dislocation density about 56 ∼ 59 %. The present results clearly show that the combination of RIB pretreatment and proper post annealing conditions results in the improved properties of GaN films grown by MOCVD.
|Journal||Journal of the Korean Physical Society|
|Issue number||SUPPL. Part 1|
|Publication status||Published - 2001 Dec|
ASJC Scopus subject areas
- Physics and Astronomy(all)