Relatively low-temperature processing and its impact on device performance and reliability

Fabrication of MoS2, ZnO, and IGZO transistors at low enough temperatures that are suitable for large-area/flexible electronics is presented. Evaluating critical processing conditions and approaches on device performance is critical to understanding and improving devices to enable large-area/flexible circuits for the IoT. For MoS2, a study of the implications of photoresist residue on MoS2 in the source/drain contact region was done. Results determined that an O2 plasma exposure in this location can remove the resist residue and create a robust TiOx/MoS2 contact, where an ~15x increase in mobility and ~20x reduction in contact resistance was achieved for O2 plasma treated transistors. Thin-film transistor fabrication of ZnO and IGZO as the semiconductor yielded saturation mobilities of 14.2 and 9.0 cm²/V•s, respectively. Among other parameters, the contact resistance was noticeably lower for ZnO due to its polycrystalline morphology compared to the amorphous IGZO, which was determined to be more resistive.