Characteristics of HfO2/Poly-Si Interfacial Layer on CMOS LTPS-TFTs With HfO2 Gate Dielectric and O2 Plasma Surface Treatment

Abstract—In this paper, high-performance complementary-metal–oxide–semiconductor low-temperature polycrystalline-silicon thin-film transistors (CMOS LTPS-TFTs) with HfO2 gate dielectric are fabricated on one wafer for the first time. Low threshold voltage and excellent subthreshold swing can be achieved simultaneously for N- and P-channel LTPS-TFTs without hydrogenation. In addition, the impacts of the HfO2/poly-Si interfacial layer on N- and P-channel LTPS-TFTs are also specified. In order to enhance the characteristics of HfO2 LTPS-TFT further, oxygen plasma surface treatment is employed to improve the interface quality and passivate the defects of channel grain boundaries, thus increasing the carrier mobility and reducing the phonon scattering. The CMOS LTPS-TFTs with HfO2 gate dielectric and oxygen plasma treatment would be suitable for the application of system-on-panel. Index Terms—High-κ, low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs), oxygen plasma, system-on-panel (SOP), 3-D integration. I