Fourier transformed photoreflectance characterization of interface electric fields in GaAs/GaInP heterojunction bipolar transistor wafers

We performed Fourier transformed photoreflectance (PR) spectroscopy on GaAs/Ga0.5In0.5P heterojunction bipolar transistor wafers. The use of Fourier transformation of the PR spectrum resolves the signals coming from the emitter-base and base-collector interfaces. The evaluated interface electric fields were compared with the capacitance obtained from capacitance-voltage measurements. The result for the base-collector interface is consistent with the Poisson equation. On the other hand, the atomic ordering in the Ga0.5In0.5P emitter plays an important role in determining the characteristics of the emitter-base interface. (C) 2003 American Institute of Physics.