Eung-Kwon Kim

Properties of TCO Fabricated with Annealing Temperature of Al Doped ZnO Film for Solar Cell Application

The annealing temperature effect of transparent conducting oxide film grown on glass substrate for solar cell application was studied in this paper. Using pulsed DC magnetron sputtering with 1 at% Al-doped ZnO target, TCO films were deposited on corning 7059 glass at room temperature. Al:ZnO thin films were annealed at 200, 400, 600℃ for 10 min and annealing resulted in lower biaxial compressive stress of about 1 ㎬ and increased average crystallite size in all films. The as-grown film shows the resistivity of 1 × 10?²Ωㆍ㎝ and transmittance under 80%, whereas the electrical and optical properties of film annealed at 400℃ are enhanced up to 5×10?⁴Ωㆍ㎝ and 85%, respectively.

Mechanism and CHARM2 Evaluation of P-Channel Metal Oxide Semiconductor Threshold Voltage Drop during High Density Plasma Heat-up Process

Plasma damage during the plasma deposition process is one of the most critical device characteristic issues facing complementary metal oxide semiconductor field effect transistor (CMOSFET) technology. In this paper, the CHARM2 monitoring system is used to evaluate UV damage and plasma charging damage during a high density plasma chemical vapor deposition (HDP-CVD) heat-up process. As a result, the amount of UV damage and negative charging damage is increased as the HDP-CVD heat-up process source power is increased. The main cause of P-channel metal oxide semiconductor field effect transistor (PMOSFET) threshold voltage drop is UV photon facilitated gate oxide electron trapping at the gate oxide and substrate P-channel interface during the HDP-CVD heat-up process. In N-channel metal oxide semiconductor field effect transistor (NMOSFET), when negative gate voltage stress is increased, gate oxide energy bend is flattened. Electrons cannot be trapped at the gate oxide and substrate N-channel interface. Therefore, the NMOSFET threshold voltage is constant during the HDP-CVD heat-up plasma process.

Properties of the Various Power Ratio in GZOB/AU Multilayers

We investigated the effects of power ratio on the electrical and optical properties of Au based Ga-, B- codoped ZnO(GZOB) thin films. GZOB thin films were deposited on Au based poly carbonate(PC) substrate with various power in the range from 60 to 120 W by DC magnetron sputtering. In the result, GZOB films at 100 W exhibited a low resistivity value of , and a visible transmission of 80 % with a thickness of 300 nm. This result indicated that the addition of Ga and B in ZnO films leads to the improvement of conductivity and transparent. From the result, we can confirm the possibility of the application as transparent conductive electrodes.

The Preferred Orientation and Morphology Characteristics of AlN Thin Films Prepared by RF Power Under Room Temperature Process

In this paper, we investigated the (002) preferred orientation and morphology characteristics of AlN thin film by using reactive rf sputtering. Additionally, AlN thin films grown in the range from 150 to 300 W were studied under room temperature without substrate heating and post annealing. Sputtered AlN thin films were well grown on Si substrates and the (002) main peak in XRD patterns showed the highest intensity at 300 W with degree of full width at half-maximum (FWHM). As increased RF power, the surface roughness was increased from 1.0 to 3.4 nm. In Fourier transformation infrared spectroscopy (FTIR), (TO) and (TO) mode closed to AlN thin film confirmed the changes with increasing the intensity rate. From these results, we could confirm a chance of the growth of AlN thin film by only low temperature.

Influence of Residual Oxygen on the growth of AlN Thin Films with Substrate Temperature

Aluminum nitride (AlN) thin films have been deposited on Au electrodes by using reactive RF magnetron sputtering method in a gas mixture of Ar and at different substrate temperature. It was found that substrate temperature was varied in the range up to , highly c-axis oriented film can be obtained at with full width at half maximum (FWHM) . Increase in surface roughness from 3.8 nm to 5.9 nm found to be associated with increase in grain size, with substrate temperature; however, the AlN film fabricated at exhibited a granular type of structure with non-uniform grains. The Al 2p and N 1s peak in the X-ray photoelectron spectroscopy (XPS) spectrum confirmed the formation of Al-N bonds. The XPS spectrum also indicated the presence of oxynitrides and oxides, resulting from the presence of residual oxygen in the vacuum chamber. It is concluded that the AlN film deposited at substrate temperature of exhibited the most desirable properties for the application of high-frequency surface acoustic devices.

Fabrication of Li 2 CO 3 -doped Thin Film Bulk Acoustic Resonator and Structural, Electrical Properties as a Function of Annealing Temperatures

In this study, we fabricated FBAR(film bulk acoustic resonator) by using as a function of annealing temperature and concentrated on effect of frequency characteristic of FBAR. The results show that the annealing affects resistivity and crystallity. The optimum properties were observed for film annealed at . The resistivity was and the roughness was 21.10 nm. And the return loss is improved from -24.9 at to -29.8 at without the resonant frequency change. We finally confirmed the improvement on the frequency characteristics of FBAR device by annealing process at the optimized condition.

Effect of Annealing on the Structural, Electrical and Optical Characteristics of Ga-doped ZnO(GZO)films

In this study we present the effect of annealing temperatures on the structural, electrical and optical characteristics of Ga-doped ZnO (GZO) films. GZO target is deposited on coming 7059 glass substrates by DC sputtering. and then GZO films are annealed at temperatures of 400, 500, in air ambient for 20 min. in this case of as-grown film, it shows the resistivity of and transmittance under 85%, whereas the electrical and optical properties of film annealed at are enhanced up to and 90%, respectively.

Dependences of Various Substrate Temperature on the Structural and Electrical Properties of ZnO Thin Films deposited by RF Magnetron Sputtering

In this study we investigated the variation of the substrate temperatures using RF sputtering to identify the effect on the structure and electrical properties by c-axis orientation of ZnO thin film. ZnO thin films were prepared on Al/Si substrate. In our experimental results, ZnO thin film at was well grown with (002) peak of ZnO thin film, the thin film showed the high resistivity with the value of and the roughness with 27.06 nm. As increased the substrate temperatures, the grain size of ZnO thin films was increased. From these results, we could confirm the suitable substrate temperature of ZnO thin films for FBAR(film bulk acoustic resonator).