Papers by Author: Sa Kyun Rha

Abstract: SiO2 films were prepared by atomic layer deposition (ALD) technique, and their physical and electrical properties were characterized for being applied as a gate insulator of low-temperature polysilicon thin-film transistors. ALD SiO2 films were deposited at 350–400 oC using alternating exposures of SiH2Cl2 and O3/O2, and the characteristics of the deposited films were improved with increasing deposition temperature. The ALD films deposited at 400 oC exhibited integrity, surface roughness and leakage current better than those of the conventional plasma-enhanced chemical vapor deposition (PECVD) films.

Abstract: The surface modification of polyimide (PI) by the irradiation of 3 keV He+, Ne+ and Ar+ ions was studied using XPS and AFM at various ion dose ranging from 1􀂯1014 to 1􀂯1017 ions/cm2. The change of surface roughness of PI by 3 keV inert ions was closely connected to the change of surface composition. At low doses below 5􀂯1015 ions/cm2, the surface of polyimide was carbonized by ion irradiations, showing rough surfaces. At higher ion doses, the surface composition was saturated due to the accumulation of damages, and the surface morphology became smoother as compared with the low dose case.