Benjamin T.-H. Lee Pages 42 - 49 ( 8 )
Background: A hydrogen-based Ion-Cut layer-transfer technique, the so-called Ion-Cut or Smart-Cut processing, has been used in transferring a semiconductor membrane onto a desired substrate to reveal unique characteristics on a nanoscale size and to build functional electronic and photonic devices that are used for specific purposes. For example, the sub-100 nm thick silicon membrane transferred onto an insulator became a key substrate for fabricating nanoscale integrated circuit (IC) devices. Recent U.S. patents have exhibited integration of various thinning approaches requiring precision of a few nanometers in fabricating large-area semiconductor nanomembranes, especially for silicon. This paper reviews published patents and work on fabricating sub-100 nm silicon membranes with welldefined features without a chemical-mechanical polishing (CMP) thinning process. This included material analysis leads to ultraprecision thickness in the sub-100 nm region.Methods: This paper combines an analysis of peer-reviewed articles and issued patents using focused review keywords of hydrogen implantation, wafer bonding, and layer splitting. The quality of selected patents was appraised based on the authors’ 20-year research experience in the field of ultrathin silicon layer-transfer technology. Results: The paper covered more than 10 U.S. patents that have been filed on hydrogen-based Ion-Cut layer-transfer techniques. These patents described approaches for inserting hydrogen ions to split at a well-defined location and then transfer the as-split silicon membrane at the nanoscale thickness onto a desired substrate. Hydrogen-trap sites, implantation energy, and interface of the distinct doped regions could define the layer-split location. The insertion of high-dose hydrogen ions could be thoroughly achieved by ion implantation, plasma ion immersion implantation (PIII), plasma diffusion, and electrolysis. Conclusion: The article concludes with the discussion of the patent-orientated review of layer-transfer techniques and makes some concrete suggestions for manufacturing the FDSOI substrate, the key material technology to fabricate nanoscale microelectronics for applications in artificial intelligence for “Industry 4.0.”
Hydrogen ion implantation, ion-cut process, layer splitting, layer transfer, nanomembrane, silicon on insulator, wafer bonding.
Department of Mechanical Engineering, National Central University, Taoyuan City