http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Structural and Electrical Properties of a Y2O3 Bu er Layer by the Two Step Process
Dong-GunLim,Jae-HyeongLee,JunsinYi 한국물리학회 2002 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.40 No.1
We investigated the structural and the electrical properties of yttrium oxide (Y$_2$O$_3$) as a buffer layer for a single transistor ferroelectric random access memory (FRAM). The Y$_2$O$_3$ films were prepared by using the rf reactive magnetron sputtering method in the presence of oxygen (O$_2$) gas. The Y$_2$O$_3$ buffer layers were deposited at a low substrate temperature below 400 $^\circ$C and were treated by rapid thermal annealing (RTA). Investigated parameters were the substrate temperature, the O$_2$ partial pressure, the post-annealing temperature, and the suppression of the interfacial SiO$_2$ layer generation. The microstructure of the Y$_2$O$_3$ films was found to depend highly on the annealing temperature and on the amount of O$_2$ gas used during the deposition process. X-ray diffraction (XRD) analysis showed the Y$_2$O$_3$ films transformed from an amorphous to a polycrystalline form when the annealing temperature was increased to 800 $^\circ$C. Also, O$_2$ partial pressures of less than 10 \% were present for the peak of monoclinic yttrium oxide. For a well-fabricated sample, we achieved a leakage current density ($J_{leak}$) on the order of 10$^{-7}$ A/cm$^2$ and a breakdown electric field ($E_{br}$) of about 2 MV/cm for the Y$_2$O$_3$ film. A capacitance versus voltage analysis yielded a dielectric constant of 8.1. We successfully achieved an interface state density of Y$_2$O$_3$/Si as low as 8.72$\times$10$^{10}$ cm$^{-2}$ eV$^{-1}$. Low interface states were obtained from the very low lattice mismatch of less than 1.75 \%.
Influence of Nitrogen Implantation on the Structural and Optical Properties of CdS Thin Films
이재형,DonggunLim,JunsinYi,KeajoonYang,D.Mangalaraj 한국물리학회 2002 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.40 No.5
The effects of nitrogen-ion implantation on vacuum-evaporated cadmium sulphide (CdS) thin films were investigated using X-ray diffraction (XRD), optical transmittance spectra, and Raman scattering studies. X-ray diffraction studies revealed that the as-deposited CdS films had a hexagonal structure with a preferential (002) orientation. The XRD patterns revealed formation of Cd metallic clusters in the ion-implanted films. The band gap of the N$^+$-implanted films decreased from 2.385 eV for the as-deposited film to 2.301 eV for maximum implantation whereas the optical absorption coefficient values increased with increasing implantation dose. Raman scattering due to the A$_l$(LO) phonon was observed at 299 cm$^{-1}$ in the as-deposited CdS film with a large full width at half maximum (FWHM). The Raman peak position did not change much whereas the FWHM increased with the ion dose. These are attributed to the effect of implantation induced lattice damage. A decrease in the area of the Raman peak of the CdS A$_l$(LO) mode is seen on implantation.