Growth and Characterization of InAs Grown on GaP for Robust Schottky Diodes
[Thesis]
Neher, Christian
Woodall, Jerry M
University of California, Davis
2019
50
M.S.
University of California, Davis
2019
A study is presented for the growth and fabrication of an indium arsenide (InAs) Schottky contact to gallium phosphide (GaP) as an alternative to traditional metal Schottky diodes for robust high-power rectification. Molecular beam epitaxy (MBE) was used to grow 100 nm of InAs onto the surface of 5x1017 cm-3 n-doped GaP vendor substrates and GaP epilayers grown by liquid phase epitaxy (LPE) with the same doping concentration. Samples of interest include those for which the InAs was grown without removing the native oxide of GaP during the MBE growth with the intention of serving as a passivation layer to reduce leakage current. The InAs to substrate GaP without oxide removal exhibited a turn-on voltage of 2.41 V and a breakdown voltage of -6.75 V, while the InAs to LPE GaP without oxide removal showed a turn-on voltage of 0.925 V and a breakdown voltage of -6.04 V. The extracted barrier heights and ideality factors by I-V characterization were 1.055 eV and 1.146 for the InAs to substrate GaP sample without oxide removal, and 1.122 eV and 1.097 for the InAs to LPE GaP without oxide removal. C-V characterization showed a barrier height of 1.260 eV for the substrate GaP sample without oxide removal, and 1.811 eV for the LPE GaP sample without oxide removal. Traditional Ti/Au on LPE GaP Schottky diodes used as a comparison showed turn on voltage of 0.56 V, a breakdown voltage of -12 V, and a barrier height of 0.912 eV. These initial results show that a Schottky contact to GaP may be achieved using InAs for the purposes of forming robust high-power rectifiers.