PEALD-deposited crystalline GaN films on Si (100) substrates with sharp interfaces Project supported by the Fundamental Research Funds for the Central Universities (Grant Nos. FRF-BR-16-018A, FRF-TP-17-022A1, and FRF-TP-17-069A1), the National Natural Science Foundation of China (Grant Nos. 61274134 and 51402064), USTB Start-up Program (Grant No. 06105033), China Postdoctoral Science Foundation (Grant No. 2018M631333), Beijing Natural Science Foundation (Grant Nos. 2184112 and 4173077), Beijing

• Published in: Chinese physics B 2019-02, Vol.28 (2)
• Main Authors: Liu, San-Jie, He, Ying-Feng, Wei, Hui-Yun, Qiu, Peng, Song, Yi-Meng, An, Yun-Lai, Rehman, Abdul, Peng, Ming-Zeng, Zheng, Xin-He
• Format: Article
• Language: English
• Subjects: gallium nitride; high resolution transmission electron microscopy; PEALD; sharp interface; x-ray reflectivity
• ISSN: 1674-1056
• DOI: 10.1088/1674-1056/28/2/026801

Polycrystalline gallium nitride (GaN) thin films were deposited on Si (100) substrates via plasma-enhanced atomic layer deposition (PEALD) under optimal deposition parameters. In this work, we focus on the research of the GaN/Si (100) interfacial properties. The x-ray reflectivity measurements show the clearly-resolved fringes for all the as-grown GaN films, which reveals a perfectly smooth interface between the GaN film and Si (100), and this feature of sharp interface is further confirmed by high resolution transmission electron microscopy (HRTEM). However, an amorphous interfacial layer (∼2 nm) can be observed from the HRTEM images, and is determined to be mixture of GaxOy and GaN by x-ray photoelectron spectroscopy. To investigate the effect of this interlayer on the GaN growth, an AlN buffer layer was employed for GaN deposition. No interlayer is observed between GaN and AlN, and GaN shows better crystallization and lower oxygen impurity during the initial growth stage than the GaN with an interlayer.