9:30 AM - 9:45 AM
[5a-C17-1] Ozone MBE Growth of N-doped β-Ga2O3 (010) Thin Films and Its Characterization
Keywords:Gallium oxide, nitrogen, doping
Semi-insulating and/or p-type layers are essential for designing various types of lateral and vertical device structures. Recently, we succeeded in developing nitrogen (N)-ion implantation doping of Ga2O3 to form current blocking layers and/or edge-termination structures in vertical Ga2O3 devices . Following the success of implantation doping, we explored in-situ N doping of Ga2O3 films during molecular beam epitaxy (MBE) growth and demonstrated the technology for the first time in this work.
N-doped Ga2O3 films were grown at 630ºC on β-Ga2O3 (010) substrates by ozone MBE with mixed source gases of O2 and N2. We used three types of source gases with N2/O2 volume ratios of 0%, 0.04%, and 0.4%. The MBE-grown films were first studied by secondary ion mass spectrometry (SIMS) to investigate N densities in the Ga2O3 films. Then, the epitaxial wafers were processed into Schottky barrier diodes (SBDs) to evaluate electrical properties of the N-doped layers.
The N densities were evaluated by a secondary ion mass spectrometry (SIMS), which showed 1.1E16 cm-3 for 0%, 3.4E16 cm-3 for 0.04%, and 1.5E17 cm-3 for 0.4% and hence it was found that N was readily incorporated into the β-Ga2O3 film during the growth. Fabricating Schottky barrier diodes (SBDs) with the epitaxial films on n+ β-Ga2O3 (010) substrates, capacitance-voltage (C-V) curves were evaluated, in which characteristics N-doped devices showed flat features ascribable to their sufficiently low carrier densities. The weak n-type conductions were observed in current density-voltage (J-V) characteristics of the SBDs. The J decreased as the N2/O2 ratio increased, such as 6.1E-6 A/cm2 for 0%, 3.5E-7 A/cm2 for 0.04%, and 1.6E-8 A/cm2 for 0.4% at the forward anode voltage of 4 V.
N-doped Ga2O3 films were grown at 630ºC on β-Ga2O3 (010) substrates by ozone MBE with mixed source gases of O2 and N2. We used three types of source gases with N2/O2 volume ratios of 0%, 0.04%, and 0.4%. The MBE-grown films were first studied by secondary ion mass spectrometry (SIMS) to investigate N densities in the Ga2O3 films. Then, the epitaxial wafers were processed into Schottky barrier diodes (SBDs) to evaluate electrical properties of the N-doped layers.
The N densities were evaluated by a secondary ion mass spectrometry (SIMS), which showed 1.1E16 cm-3 for 0%, 3.4E16 cm-3 for 0.04%, and 1.5E17 cm-3 for 0.4% and hence it was found that N was readily incorporated into the β-Ga2O3 film during the growth. Fabricating Schottky barrier diodes (SBDs) with the epitaxial films on n+ β-Ga2O3 (010) substrates, capacitance-voltage (C-V) curves were evaluated, in which characteristics N-doped devices showed flat features ascribable to their sufficiently low carrier densities. The weak n-type conductions were observed in current density-voltage (J-V) characteristics of the SBDs. The J decreased as the N2/O2 ratio increased, such as 6.1E-6 A/cm2 for 0%, 3.5E-7 A/cm2 for 0.04%, and 1.6E-8 A/cm2 for 0.4% at the forward anode voltage of 4 V.