Heavily Boron-Doped Silicon Layer for the Fabrication of Nanoscale Thermoelectric Devices

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2018-01, Vol.8 (2), p.77
• Main Authors: Ma, Zhe, Liu, Yang, Deng, Lingxiao, Zhang, Mingliang, Zhang, Shuyuan, Ma, Jing, Song, Peishuai, Liu, Qing, Ji, An, Yang, Fuhua, Wang, Xiaodong
• Format: Article
• Language: English
• Subjects: Boron; boron etch-stop; Electron beam lithography; Etching; Fabrication; Figure of merit; heavily boron-doped silicon layer; Inductively coupled plasma; Microelectromechanical systems; nanostructures; Nanotechnology; Nanowires; Silicon; silicon nanowire; Thermal conductivity; thermoelectric; Thermoelectricity
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano8020077

Heavily boron-doped silicon layers and boron etch-stop techniques have been widely used in the fabrication of microelectromechanical systems (MEMS). This paper provides an introduction to the fabrication process of nanoscale silicon thermoelectric devices. Low-dimensional structures such as silicon nanowire (SiNW) have been considered as a promising alternative for thermoelectric applications in order to achieve a higher thermoelectric figure of merit (ZT) than bulk silicon. Here, heavily boron-doped silicon layers and boron etch-stop processes for the fabrication of suspended SiNWs will be discussed in detail, including boron diffusion, electron beam lithography, inductively coupled plasma (ICP) etching and tetramethylammonium hydroxide (TMAH) etch-stop processes. A 7 μm long nanowire structure with a height of 280 nm and a width of 55 nm was achieved, indicating that the proposed technique is useful for nanoscale fabrication. Furthermore, a SiNW thermoelectric device has also been demonstrated, and its performance shows an obvious reduction in thermal conductivity.