Fully Bottom‐Up Waste‐Free Growth of Ultrathin Silicon Wafer via Self‐Releasing Seed Layer

• Published in: Advanced materials (Weinheim) 2021-10, Vol.33 (41), p.e2103708-n/a
• Main Authors: Hong, Ji‐Eun, Lee, Yonghwan, Mo, Sung‐In, Jeong, Hye‐Seong, An, Jeong‐Ho, Song, Hee‐eun, Oh, Jihun, Bang, Junhyeok, Oh, Joon‐Ho, Kim, Ka‐Hyun
• Format: Article
• Language: English
• Subjects: Commercialization; Copper; Electronics; Epitaxial growth; epitaxial Si; kerfless wafer fabrication; Plasma; self‐releasing layer; Semiconductor devices; Silicon substrates; Silicon wafers; single‐batch reactor; Stretchability; ultrathin Si
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202103708

The fabrication of ultrathin silicon wafers at low cost is crucial for advancing silicon electronics toward stretchability and flexibility. However, conventional fabrication techniques are inefficient because they sacrifice a large amount of substrate material. Thus, advanced silicon electronics that have been realized in laboratories cannot move forward to commercialization. Here, a fully bottom‐up technique for producing a self‐releasing ultrathin silicon wafer without sacrificing any of the substrate is presented. The key to this approach is a self‐organized nanogap on the substrate fabricated by plasma‐assisted epitaxial growth (plasma‐epi) and subsequent hydrogen annealing. The wafer thickness can be independently controlled during the bulk growth after the formation of plasma‐epi seed layer. In addition, semiconductor devices are realized using the ultrathin silicon wafer. Given the high scalability of plasma‐epi and its compatibility with conventional semiconductor process, the proposed bottom‐up wafer fabrication process will open a new route to developing advanced silicon electronics. A fully bottom‐up technique for fabricating a self‐releasing ultrathin silicon wafer without sacrificing any of the substrate is presented, whereas conventional technologies waste large amounts of such material. A plasma‐assisted epitaxially grown silicon seed layer with a self‐organized nanogap is a key for the realization of the fully bottom‐up process. The results represent a technological breakthrough in advanced silicon microelectronics and photovoltaics.