High yield preparation of flexible single-crystalline 4H-silicon carbide nanomembranes via buried micro-trenches

Abstract We present the fabrication of flexible single-crystalline 4H-silicon carbide (SiC) nanomembranes (NMs) with a centimeter size. The 4H–SiC NMs has been released from a 4H–SiC-on-insulator (4H–SiCOI) wafer and transferred to a flexible adhesive tape. By introducing buried micron trenches (BMTs) in the sacrificial buried oxide (BOX) layer in 4H–SiCOI, the lateral etching rate is increased by about three times, crucial to the fabrication of large-size 4H–SiC NMs with a high yield. The prepared 4H–SiC NMs show single-crystalline quality, ultra-smooth surface, and excellent ultraviolet (UV) absorption performance, paving the way toward the development of 4H–SiC based flexible and stretchable optoelectronic devices. The proposed BMTs assisted release method also provides a universal and effective way to obtain large scale and intact single-crystalline NMs for flexible applications.