3D Self‐Assembled Microelectronic Devices: Concepts, Materials, Applications

Abstract

www.advmat.de www.advancedsciencenews.com photolithography techniques. New amorphous semiconducting materials are involved in the development of flexible electronics based on high-performance compounds that include organic [82] and inorganic (e.g., copper oxide [83] or indium-gallium-zinc oxide (IGZO) [84] ) semiconductor possessing, for instance, the transparency [85] required in optoelectronic applications. Once fabricated on polymeric ultrathin substrates, these devices offer the flexibility, stretchability, and imperceptibility [85][86][87] for onskin (Figure 3 a,b,d) biomedical applications, such as biosensors capable of conformally wrapping a soft or irregularly shaped 3D biological sample such as a cancer cell or a pollen grain. [88] Demonstrating outstanding mechanical stability, thin-film materials, in particular semiconductors, are superior candidates for 3D applications compared to monocrystalline semiconductors. [87,89,90] Good examples are amorphous oxides and some organic molecular semiconductors [82] (Figure 3b-d) which are particularly attractive for 3D self-assembled microelectronics. By employing substrates with a thickness in the micro-and submicrometer range (Figure 3) many issues associated with mechanical stress on the surface could be mitigated, demonstrating the increased robustness and reliability of thinfilm electronics. [87,89] Electronic skin (e-skin) (Figure 3a,b,d), for Adv. Mater. 2020, 32, 1902994 Adv. Mater. 2020, 32, 1902994 Figure 3. Thin-film flexible electronic devices and applications. a) Mechanical prosthesis with stretchable electronic skin. Adapted with permission. [97] Copyright 2014, Springer Nature. b) Schematics and photograph of imperceptible organic electronics equipped with tactile active sensor matrix. Adapted with permission. [87] Copyright 2013, Springer Nature. c) Complex circuits with 8-bit microprocessors made of 3381 organic thin-film transistors. Adapted with permission. [98] Copyright 2012, IEEE. d) Ultrathin substrate combined with high-performance indium-gallium-zinc oxide (IGZO) circuitry paving the way for active medical devices on contact lenses. [85] Adapted with permission. [85] Copyright 2014, Springer Nature.

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