Study on Phase Transition of Zn1-XMgXO Thin Films Grown by MOCVD Process

We have grown Zn
_1-x
Mg
_x
O films by MOCVD process with a gas mixture of diethylzinc(DEZ), H
₂
O and bis-methylcyclopentadienyl-Mg {MeCp
₂
Mg:(CH
₃
C
₅
H
₄
Mg)}. We found that phase transition from wurtzite to rocksalt structure was strongly influenced by substrate temperature and MeCp
₂
Mg gas phase concentration. Wurtzite structure was dominant under high substrate temperature, and rocksalt was dominant under high MeCp
₂
Mg gas phase concentration. This behavior was in good agreement with our calculation of enthalpy for each structure. We also found that film structure was not uniform in growth direction under low substrate temperature due to the phase transition. These result suggested that higher growth temperature were preferable to the growth of high Mg content wurtzite Zn
_1-x
Mg
_x
O for the MOCVD process