| AVS 66th International Symposium & Exhibition | |
| Electronic Materials and Photonics Division | Tuesday Sessions |
| Session EM+OX+TF-TuA |
| Session: | Nikolaus Dietz Memorial Session: Wide and Ultra-wide Band Gap Materials and Devices |
| Presenter: | Luke Lyle, Carnegie Mellon University |
| Authors: | L.A.M. Lyle, Carnegie Mellon University K. Jiang, Carnegie Mellon University E. Favela, Carnegie Mellon University D. Moody, Carnegie Mellon University T. Lin, Carnegie Mellon University P. Chung, Carnegie Mellon University K. Das, North Carolina State University Z. Galazka, Leibniz-Institut für Kristallzüchtung, Germany A. Popp, Leibniz-Institut für Kristallzüchtung, Germany G. Wagner, Leibniz-Institut für Kristallzüchtung, Germany L.M. Porter, Carnegie Mellon University |
| Correspondent: | Click to Email |
Over the past decade beta-gallium oxide (β-Ga2O3) has accrued increased interest due to its ultrawide bandgap of around 4.6 eV, superior figures of merit for numerous electronic and optoelectronic applications, and the ability to produce single-crystal melt-grown substrates. Considering these factors, β-Ga2O3 has been primarily pursued for applications as high-power electronics, of which the understanding and development of Schottky and ohmic metal contacts is critical. In this study we characterized the electrical properties of electron-beam evaporated Ni, Mo, Au and other metal Schottky contacts to (100) β-Ga2O3 substrates. Prior to deposition of the metals, the Ga2O3 surface was cleaned via a 10% HCl solution followed by a clean in boiling 30% H2O2 solution at 85°C. Ti/Au was deposited via electron-beam evaporation and annealed at 400°C in an Ar atmosphere for use as ohmic contacts. The ideality factors, barrier heights, and doping densities were calculated from I-V and C-V measurements, which showed excellent agreement in most cases; I-V-T measurements are also planned as a complementary method to determine electrical transport behavior as a function of temperature. From our measurements it was observed that the Schottky barrier heights tended to increase as a function of the metal workfunction. These results are in contrast to our prior measurements of Schottky contacts on (-201) β-Ga2O3, which showed little to no correlation between Schottky barrier height and metal workfunction. In this presentation we will compare the electrical behavior of the various metal contacts on (100) β-Ga2O3, including the extracted ideality factors (~1.05–1.2) and Schottky barrier heights (~0.9–2 eV). The results will be discussed in the context of important processing conditions, as well as structural, optical, and morphological characteristics of (100) and (-201) -Ga2O3 substrates as determined from x-ray diffraction, UV-visible spectroscopy, atomic force microscopy, and other techniques.