Growth of Highly Conductive n-Type Al<sub>0.7</sub>Ga<sub>0.3</sub>N Film by Using AlN Buffer with Periodical Variation of V/III Ratio
Zhang Jie; Guo Li-Wei; Xing Zhi-Gang; Ge Bing-Hui; Ding Guo-Jian; Peng Ming-Zeng; Jia Hai-Qiang; Zhou Jun-Ming; Chen Hong
Журнал:
Chinese Physics Letters
Дата:
2008-12-01
Аннотация:
High quality and highly conductive n-type Al<sub>0.7</sub>Ga<sub>0.3</sub>N films are obtained by using AlN multi-step layers (MSL) with periodical variation of V/III ratios by low-pressure metalorganic chemical vapour deposition (LP-MOCVD). The full-width at half-maximum (FWHM) of (0002) and (1015) rocking curves of the Si-doped Al0.7Ga0.3N layer are 519 and 625 arcsec, respectively. Room temperature (RT) Hall measurement shows a free electron concentration of 2.9 × 10<sup>19</sup> cm<sup>−3</sup>, and mobility of 17.8 cm<sup>2</sup>V<sup>−1</sup>s<sup>−1</sup>, corresponding to a resistivity of 0.0121 ω cm. High conductivity of the Si-doped AlGaN film with such high Al mole fraction is mainly contributed by a remarkable reduction of threading dislocations (TDs) in AlGaN layer. The TD reducing mechanism in AlN MSL growth with periodical variation of V/III ratio is discussed in detail.
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