Abstract
In recent years, a lot of wide bandgap semiconducting rare metal oxide (REO) materials have been widely used in numerous electrical elements. But, samarium oxide (Sm2O3), one of rare metal oxides still has not been investigated widely. In this thesis, we were focused on structural and electrical properties of samarium oxide. Next, we have introduced samarium oxide as gate dielectric insulator of transparent thin film transistors, and then prepared active layer with IZO or IGZO respectively, finally analyzed their characteristics by measurement. The first part of this thesis demonstrates the characteristics of MIM capacitors. The Sm2O3 dielectric layer of MIM capacitor was deposited on ITO glass by reactive sputtering and used plasma or annealing treatments. Further, we successfully fabricated transparent thin film transistors (TTFTs) using IZO or IGZO as active layer and Sm2O3 as gate dielectric insulator at room temperature. The enhancement mode operation IZO TFT exhibited outstanding characteristics of on/off ratio, threshold voltage, saturation mobility, sub-threshold swing were 9.49×106, 1.196(V), 126.9(cm2/V-s), 0.308 (V/decade). The IGZO TFT showed stabilized characteristics in the light of on/off ratio, threshold voltage, saturation mobility, sub-threshold swing were 1.63×108, 1.962(V), 46.8(cm2/V-s), 0.197(V/decade). The second part of this thesis successfully demonstrates HfO2 was incorporated with Sm2O3 thin film by co-sputtering for reducing leakage and increasing capacitance of MIM capacitor. Next, we fabricated TTFTs using IZO or IGZO as active layer respectively and SmHfO as gate dielectric insulator at room temperature. The IZO TFT exhibited characteristics of on/off ratio, threshold voltage, saturation mobility, sub-threshold swing were 1.89×106, 2.577(V), 12.4(cm2/V-s), 0.322(V/decade). The IGZO TFT showed stabilized characteristics in the light of on/off ratio, threshold voltage, saturation mobility, sub-threshold swing were 1.65×107, 1.405(V), 14.9(cm2/V-s), 0.2(V/decade).