Tetramethysilane-assisted enhancement of diamond nucleation on silicon substrate

• Published in: Surface & coatings technology 2018-09, Vol.349, p.959-962
• Main Authors: Yi, Yong, Xiong, Ying, Zhuang, Hao, Yang, Bing, Wang, Bing, Jiang, Xin
• Format: Article
• Language: English
• Subjects: Bias; Bias-enhanced nucleation; Chemical composition; Chemical vapor deposition; Density; Diamond nuclei; Diamonds; Flow velocity; HRTEM; Microwave plasmas; Nucleation; Nucleation behavior; Nuclei; Organic chemistry; Silicon; Silicon substrates; Substrates; Tetramethylsilane; Transmission electron microscopy; X ray photoelectron spectroscopy
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2018.06.087

This paper describes the effect of tetramethylsilane (TMS) on diamond nucleation on Si substrate under an applied bias voltage of 120 V, performed in a modified microwave plasma chemical vapor deposition (MPCVD) reactor. The introduction of TMS in the CH4/H2 plasma leads to a significant enhancement of nucleation density of diamond nuclei, namely from (3.7 ± 0.2) × 107/cm2 without the introduction of TMS to (4.7 ± 0.5) × 1010/cm2 at the TMS flow rate of 4 sccm. On the contrary, further increasing in the TMS flow rate to 8 sccm slightly reduces the nucleation density of diamond nuclei to (2.1 ± 0.3) × 1010/cm2, along with the increase in average size of diamond nuclei. High-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) allow us to study the microstructural and chemical composition evolution of Si/diamond interface. The obtained results suggest that bias-enhanced nucleation of diamond on Si substrate exhibits a direct relationship with the TMS flow rate. •Diamond nucleation was enhanced by introducing TMS in the CH4/H2 plasma.•Diamond nucleation was generated in condensed amorphous carbon at low TMS flow rate.•At high TMS flow rate diamond was nucleated from the active sites of SiC phase.•Diamond nucleation mechanism strongly depended on the TMS flow rate.