Regensburg 2019 – wissenschaftliches Programm
HL 9.5: Vortrag
Montag, 1. April 2019, 16:00–16:15, H34
Low-frequency noise characterization of MOCVD-grown β-Gallium Oxide — •Christian Golz1, Günther Wagner2, Andreas Popp2, Fariba Hatami1, and W. Ted Masselink1 — 1Department of Physics, Humboldt-Universität zu Berlin, Newton-Str. 15, D-12489 Berlin, Germany — 2Leibniz Institute for Crystal Growth, Max-Born-Str. 2, 12489 Berlin, Germany
Low-frequency noise spectroscopy was used to characterize β-Ga2O3 epilayers. These high-quality Si-doped layers were homoepitaxially grown by metal-organic chemical vapour deposition (MOCVD) on insulating Mg-doped β-Ga2O3 substrates. For noise measurements, Greek cross structures were processed using optical lithography. Hot H3PO4 etch was applied to process the mesa structures. Ohmic Cr/Au contacts were processed by thermal evaporation. Low-frequency noise is produced by the fluctuations in conductivity in a material. The 1/f noise intensity was used to determine a room temperature Hooge factor below 10−4. This value indicates a high structural quality of the epilayer. Generation-recombination noise was analyzed between 80 K and 400 K. Several trap levels were found with characteristic time constants depending exponentially on temperature. Activation energies for these levels were determined to be in the range from 30 meV to 300 meV.