XIN Xiao-long, ZUO Ran, TONG Yu-zhen etc. Surface Reaction Mechanism on GaN MOVPE Growth[J]. Chinese Journal of Luminescence, 2015,36(7): 744-750 DOI: 10.3788/fgxb20153607.0744.
Surface initial growth process of GaN film in MOVPE is studied by DFT theory of quantum chemistry. By calculating the adsorption energies of GaCH
3
and NH
3
at main adsorption sites of GaN (0001)-Ga surface
it is found that energies of GaCH
3
at four adsorption sites are similar
thus GaCH
3
is easy to diffuse on the surface. The energies of NH
3
at four adsorption sites are much different. The most stable adsorption site for NH
3
is Top
and the large energy barrier exist for NH
3
migrating from Top to other sites. Based on the energy analysis
the initial GaN surface growth mechanism is proposed for GaN (0001)-Ga surface
with NH
3
and GaCH
3
as growth precursor and ring structured core as final form. In the process of the ring structured core growth
the first GaN core growth need three NH
3
and one GaCH
3
which can be expressed as Ga(NH
2
)
3
. The second GaN core growth can use one existing N as coordination atom
so only two NH
3
and one GaCH
3
are needed. The two GaN core can be expressed as (NH
2
)
2
Ga-NH-Ga (NH
2
)
2
. The third GaN core growth can use two existing N as coordination atoms
so only one NH
3
and one GaCH
3
are needed. The third GaN core forms a ring structure which can be expressed as Ga
3
(NH)
3
(NH
2
)
3
. The subsequent growth will repeat the process of the second and third core growth
so as to realize the continuous steps of GaN film growth.
关键词
GaN薄膜MOVPEDFT表面反应
Keywords
GaNMOVPEDFTsurface reaction
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