Polarity inversion of GaN films by trimethyl-aluminum preflow in low-pressure metalorganic vapor phase epitaxy growth

被引:38
作者
Lim, DH
Xu, K
Arima, S
Yoshikawa, A
Takahashi, K
机构
[1] Chiba Univ, Dept Elect & Mech Engn, Venture Business Lab, Ctr Frontier Elect & Photon,Inage Ku, Chiba 2638522, Japan
[2] Teikyo Univ Sci & Technol, Dept Media Sci, Uenohara, Yamanashi 4090193, Japan
关键词
D O I
10.1063/1.1471384
中图分类号
O59 [应用物理学];
学科分类号
摘要
The polarity of GaN films grown on nitrided (0001) sapphire substrates by low-pressure metalorganic vapor phase epitaxy was controlled by trymethyl-aluminum (TMAl) preflow prior to the growth of GaN buffer layer. The TMAl preflow served as forming a few monolayers of Al to modify the nitrided sapphire surface. The effects of the TMAl preflow on GaN epilayer polarities were investigated by coaxial impact collision ion scattering spectroscopy. It was shown that, by increasing the TMAl preflow time, the polarities of GaN epilayers were changed from a N polarity to a mixed polarity, and finally to a pure Ga polarity when the preflow time was over than 5 s. A schematic model of "two monolayers of Al" was proposed to understand the related mechanisms. The effects of the TMAl preflow on the epilayer quality were also evaluated by high-resolution x-ray diffraction. (C) 2002 American Institute of Physics.
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收藏
页码:6461 / 6464
页数:4
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