Résumé
GaInP/GaAs HBTs with and without a base epitaxial regrowth are studied via low-frequency noise measurements. Current spectral densities are analysed versus bias and geometry. For samples without regrowth, noise sources are mostly located at the extrinsic base surface, whereas recombinations are located throughout the whole emitter-base junction for the other type of transistors. In this latter case, an exodiffusion of H during thermal annealing is suggested to be the principle cause for the observed phenomena.