| 초록 |
Gallium oxide is emerging ultra wide band gap oxide material for power semiconductors and photonic devices applications. Five different crystal structures are reported, however, monoclinic beta Ga2O3 and rhombohedral alpha Ga2O3, which have band gap energies of 4.9 and 5.2 eV at RT, respectively, are mostly studied. Due to the large breakdown field of 8MV/cm, which is about 2.5 times of that of GaN, it has attracted attention for power semiconductor devices. Many research groups from Japan, EU, and USA have reported promising results on FET and SBD devices as well as growing epilayers. In fact, international workshops on gallium oxide and related materials were successfully held (IWGO 2015 and 2017), in which we presented. Comparing to GaN, the strong benefit of Ga2O3 is that single crystal substrates (n-type and insulating) are commercially available. For the growth of epilayers mist CVD, HVPE, MOCVD, and MBE technologies have been applied. For the beta Ga2O3 growth it is mostly homoepitaxial since the provided substrate is beta Ga2O3. For the rhombohedral structure epitaxial alpha Ga2O3, most of results are heteroepitaxial on sapphire substrates. In this study, we will present our recent results focused on homoepitaxy: Growth behaviors and evolution by MBE, defect characterization, and doping. |
