Fabrication of Si/SiO2/Au nanoparticles/HfO2 MOS capacitor structure by spin coating method

In this work, a Metal-Oxide-Semiconductor (MOS) capacitor (Si/SiO₂/Au nanoparticles/HfO₂) has been fabricated. Gold (Au) nanoparticles with particle size of about 3.3 nm were synthesized by chemical reduction method. Then the self-assembled gold nanoparticles were attached to 3-aminopropyltrimethoxysilane (APTMS) modified silicon oxide substrates by the spin coating method. With the spin coating method, the gold nanoparticles can be fabricated onto 5.0 nm thermally grown silicon oxide with highly packing density of 1 × 10¹² cm^-2 in a short processing time. Finally, the sol-gel derived HfO₂ layer was spin coated to construct a Si/SiO₂/Au nanoparticles/HfO₂ structure. The MOS structure embedded with Au nanoparticles showed well defined counterclockwise C-V hysteresis curves which indicating a good memory effect. The flat-band voltage shift was about 2.7 V at a swapping voltage between ±5 V. Furthermore, the MOS structure embedded with Au nanoparticles behaved a desirable retention characteristic up to 10⁴s. We have succeeded to fabricate the Metal-Oxide-Semiconductor capacitor structure (Si/SiO₂/Au nanoparticles/HfO₂) by a spin coating method. The spin coating method has many advantages like short fabrication time, high uniformity, and better reproducibility when compared with the traditional immersion method. Therefore, the spin coating method has the potential to be applied to nanofabrication processes in mass production.