Plasma enhanced atomic layer deposition of crystallized gallium phosphide on Si with tri-Ethylgallium and tri-tert-Butylphosphine

• Published in: Applied surface science Vol. 619; p. 156727
• Main Authors: Yun, SeongUk, Kuo, Cheng-Hsuan, Lee, Ping-Che, Ueda, Scott T., Wang, Victor, Kashyap, Harshil, Mcleod, Aaron J., Zhang, Zichen, Winter, Charles H., Kummel, Andrew C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.05.2023
• Subjects: Gallium phosphide; Local epitaxy growth; Nucleation; Plasma enhanced atomic layer deposition; TEGa; tri-TBP; tri-TBP; Plasma enhanced atomic layer deposition; Nucleation; Gallium phosphide; TEGa; Local epitaxy growth
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2023.156727

[Display omitted] •Tri-TBP dry clean improved the functionalization of Si surface during nucleation.•GaP epi-layers with enhanced crystallinity were homogeneously deposited on Si.•Nucleation and growth mechanisms of GaP atomic H ALD were proposed.•Local epitaxy growth of GaP atomic H ALD was observed on mis-cut Si. 25 ∼ 30 nm thick polycrystalline gallium phosphide (GaP) films with high P / Ga atomic ratios were deposited on Si (100) using a plasma enhanced atomic layer deposition (PE-ALD) process with triethyl gallium (TEG), tri-tertiary butyl phosphide (tri-TBP), and atomic hydrogen. The key is chemical functionalization of the Si (100) surface since the wet-cleaned Si surface is nearly inert to TEG and tri-TBP. In-situ Auger spectroscopy was employed to identify the most successful functionalization which employed a gas phase mixture of atomic hydrogen and tri-TBP consistent with formation of a surface phosphide layer on Si(100); this layer efficiently nucleated the PE-ALD of GaP. The crystallinity and surface roughness of GaP films were tuned by controlling the pulse length of atomic H plasma, showing the self-limiting ALD film growth with 2.7 Å/cycle. The optimal crystallized GaP thin film on 6°-miscut Si showed local epitaxy growth of homogeneous GaP epi-layers in transmission electron microscopy (TEM).