AVS 50th International Symposium
    Semiconductors Monday Sessions
       Session SC-MoM

Paper SC-MoM9
Formation of Zinc-blende-structure GaN Thin Films on Si Substrates by Radio Frequency Planar Magnetron Sputter Deposition

Monday, November 3, 2003, 11:00 am, Room 321/322

Session: Heteroepitaxy of Wide Bandgap Semiconductors
Presenter: J.H. Kim, University of Florida
Authors: J.H. Kim, University of Florida
P.H. Holloway, University of Florida
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GaN thin films were grown on silicon (100) and (111) wafers with no intentional substrate heating by radio frequency (RF) planar magnetron sputtering of a bulk-GaN-crystal target in a pure nitrogen atmosphere. The N@sub2@ gas pressure during the film growth was varied from 7 to 50 mTorr to investigate the influence of energetic particle bombardment on the phase evolution in the deposited GaN films. The GaN films grown at pressures higher than 20 mTorr exhibited a randomly-oriented polycrystalline wurtzite structure. For pressures between 10 and 20 mTorr, both zinc-blende and wurtzite phases were observed and the relative fraction of the zinc-blende phase increased at lower pressure. Below 10 mTorr, the deposited GaN films had a predominant zinc-blende structure with a preferred orientation in the [111] direction perpendicular to the film surface. As the N@sub2@ gas pressure was reduced from 50 to 7 mTorr, the internal stress of GaN films became increasingly compressive as a result of atomic peening effects and reached a value of about 3.2 x 10@super10@ dyne/cm@super2@ at 7 mTorr. The mechanism responsible for the formation of metastable zinc-blende GaN will be discussed in relation to the energetic particle bombardment of GaN films during growth.