| 초록 |
α-Ga2O3 has been reported to have a large bandgap energy (Eg = 5.3 eV), and as a transparent semiconducting material, it has high potential for various device applications such as deep UV photodetectors, gas sensors, and field-effect transistors. α-Ga2O3 is known to possess five different crystal structures, specifically, α-,β-,γ-, ε-, and δ-phases. Among them, α-Ga2O3 exists in a meta-stable state, and liquid phase growth is impossible, but growth can be achieved by a vapor phase growth method such as hydride vapor phase epitaxy(HVPE). HVPE is a deposition equipment of CVD type, which is capable of rapid deposition rate and crystal growth of high purity, and is widely used in the Ⅲ-Ⅴ semiconductor industry. α-Ga2O3 can grow on low-cost sapphire substrates, and α-Ga2O3 and sapphire have the same corumdum structure. The lattice mismatch between α-Ga2O3 and sapphire is ~4.5% and ~3.3% on the a- and c-axis, respectively. Therefore, in this study, the vapor phase growth of α-Ga2O3 using HVPE with excellent deposition rate was studied, and c-plane sapphire substrate was used as the substrate. In addition, studies have been carried out to determine the optimal temperature range and optimal Ⅵ/Ⅱ ratio to obtain the phase change suppression section and the high-crystalline α-Ga2O3 thin film depending on the temperature of α-Ga2O3. The growth rate of the thin film and the surface state of the thin film were confirmed by scanning electron microscope(SEM) and the crystallinity was confirmed by using X-ray diffraction(XRD). The absorption wavelength and transmittance were also confirmed by UV-Vis Spectrophotometer. |
