N-p-n AlGaAs/GaAs and GaInP/GaAs (double) heterojunction bipolar transistors with thin base widths down to 200 Angstrom have been fabricated, and their collector and base current-voltage characteristics have been studied. The experimental results show that the surface recombination current and the base bulk recombination current are lower in 200 Angstrom base AlGaAs/GaAs HBTs than in comparable devices with 500 Angstrom base width. The experiment also showed that the surface recombination currents and the sum of other base recombination currents (the base bulk recombination current, the base-emitter junction space charge recombination current, and the base-to-emitter back-injected current) are significantly lower in GaInP/GaAs (D)HBTs than that in comparable AlGaAs/GaAs HBTs. For the thin base GaInP/GaAs (D)HBTs, the current gain measurements with different emitter sizes demonstrates high current gain, low emitter edge recombination and negligible emitter-size effect.