Ohmic contact formation mechanism of the Au/Ge/Pd/n-GaAs system formed below 200 °C

We report the ohmic contact formation mechanism of the low resistance (∼1×10−6 Ω cm2) Au/Ge/Pd contact to n‐GaAs annealed at 175 °C. Cross‐sectional transmission electron microscopy and Rutherford backscattering spectrometry were utilized in this study. It is found that the solid phase regrowth process, interdiffusion between Au and Ge, and the enhancement of the conductivity of the excess Ge layer are responsible for the observed low contact resistivity.