| dc.description.abstract | With the continuous development of technology, the demand for electronic products is becoming smaller and more convenient. The chips in electronic products will also become smaller and smaller, which means that the area of capacitors inside the chip also needs to be reduced. In the fabrication of capacitors, traditionally used dielectric materials such as Si3N4 and SiO2 have the advantages of high chemical stability and low leakage, but their low dielectric
constant is not enough to meet the needs of gradually shrinking capacitors. Therefore, traditional dielectric materials are replaced by High-k materials or sandwich structures consisting of multiple dielectric layers. However, High-k materials have disadvantages such as easy leakage and capacitance instability. Most of them require expensive processes, such as atomic layer deposition or laser pulse deposition, to ensure quality. The sandwich structure dielectric layer also has some limitation of complex processes. Therefore, in this research, relatively low-cost magnetron sputtering was used to effectively improve the dielectric constant of traditional dielectric materials by changing the sputtering environment and inserting an ITO interlayer to meet the needs of high capacitance values.
In chapter 3, Si-nitride films sputtered using N2/Ar mixed gas flow and pure Ar ambient were prepared. Si-nitride films fabricated using the Ar/N2 mixed gas flow sputtering ambient
have a dielectric constant as high as 17, which is higher than that of pure Ar gas flow sputtering. In addition, it is higher than all other reported sputtered silicon nitride films and equivalent to chemical vapor deposited silicon nitride films. In X-ray photoelectron spectroscopy analysis, it can be known that in the Si-nitride sputtered by the Ar/N2 mixed gas flow, SiNx is the dominated phase, which is related to the radiative N species during the sputtering process. The photoluminescence analysis confirmed that the Si-nitride thin film sputtered in the Ar/N2 mixed gas flow has more N vacancies than the Si-nitride thin film sputtered in pure Ar gas flow.
In chapter 4, two parallel-plate capacitors, Cu/Si-oxide/Cu (MIM) and Cu/Sioxide/Indium-Tin-Oxide/Cu (MIM-ITO), were fabricated. The capacitance of MIM-ITO structure (1365.5 pF) was measured to be much larger than MIM structure (442 pF) by four folds. The ITO interlayer enhances the “edge effect” and results in non-stoichiometric Si2O3 phase formation in Si-oxide film. Si2O3 tetrahedrons present strong spontaneous dipoles, which result in an additional net polarization in the Si-oxide film under an applied electric field. With TEM images, (222)-preferred ITO crystalline phase was observed at the Si-oxide/ITO interface and served as the growth seed layer for Si2O3-contained Si-oxide film. | en_US |