【摘 要】
：
A three-step growth process is developed for depositing high-quality aluminium-nitride (AIN) epilayers on (001) sapphire by low pressure metalorganic chemical v
【机 构】
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Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of S
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A three-step growth process is developed for depositing high-quality aluminium-nitride (AIN) epilayers on (001) sapphire by low pressure metalorganic chemical vapour deposition (LP-MOCVD). We adopt a low temperature (LT) AIN nucleation layer (NL), and two high temperature (HT) AIN layers with different Ⅴ/Ⅲ ratios. Our results reveal that the optimal NL temperature is 840-880℃, and there exists a proper growth switching from low to high Ⅴ/Ⅲ ratio for further reducing threading dislocations (TDs). The screw-type TD density of the optimized AIN film is just 7.86×106 cm-2, about three orders lower than its edge-type one of 2×109 cm-2 estimated by high-resolution x-ray diffraction (HRXRD) and cross-sectional transmission electron microscopy (TEM).
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