| Summary: | 碩士 === 國立中興大學 === 電機工程學系 === 92 === This thesis uses pulse modulation plasma technology to control the RF-on time of the pulse generator and form the different films on the different hydrogen contents and different Si-H bonding configurations. The a-Si:H films are deposited under the process parameters mentioned after. The RF-on times are set from 30ms to 5ms, the RF-off time is fixed at 30ms. The substrate temperatures are at 100℃, 150℃, 200℃. The ratio of SiH4 to H2 is 1/4, deposition pressure is 0.75 Torr and RF power is 20W. After the measurements of FTIR spectrometer for the a-Si:H films on the different process recipes, we can understand the difference of absorption peaks on 640cm-1 peak, 845 cm-1、890 cm-1、2000 cm-1、2080 cm-1 and the hydrogen contents of films range between 22.82% and 13.52%. Therefore, we the effects of the pulse modulation plasma technology and the substrate temperatures on Si-H bonding configurations. In addition, we get the refractive indices from 3.100 to 3.561 and the surface roughness from 2.365nm to 0.931nm by the measurements and analyses of UV-VIS NIR spectrometer and AFM.
The loose hydrogen structure will be relaxed by using the RETA treatment, and we will analyze the component distribution of SiH、SiH2、(SiH2)n in the films. As the RETA temperatures are set from 350℃ to 650℃ and the annealing cycles are set (2+5) times,(2+5+10) times, and (2+5+10+15) times, we check the change of the area of peak on 640 cm-1、2000 cm-1、2080 cm-1 after RETA annealing. The results show that the structure is looser, the effusion of hydrogen increases, and area of peak decreases. As increasing RF-on time and decreasing the substrate temperature. In contrary, the structure is denser and, the effusion of hydrogen decreases, and area of peak increases. As decreasing RF-on time and increasing the substrate temperature.
Finally, we will form the films on different hydrogen contents and different refractive indices by controlling the ratio of RF-on time to RF-off time of pulse modulation plasma technology. After that, the periodic multi-layer films of alternate a-Si:Hx and a-Si:Hy are fabricated on modulating the RF-on time/RF-off time and deposition time by computer control systems. The periodic a-Si:Hx and a-Si:Hy configurations will be verified by XRD whether the angle of peak of XRD analysis fit the Bragg Law, 2dsinθ=nλ.
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