The effects of hydrogen treatment on electrical properties, luminescence spectra, and deep traps in InGaAlP and InGaP have been studied. It is shown that acceptors and donors (both shallow and deep) can be effectively passivated by hydrogen. The hydrogen is found not only to passivate the main electron and hole traps in our samples, but also to generate electron traps in n-InGaAlP and hole traps in p-InGaP. The influence of hydrogen treatment mode (direct plasma or a crossed-beams source in which the low-energy ion bombardment of the surface is effectively eliminated) on hydrogen concentration and hydrogen profiles in InGaAlP are discussed. © 1994 American Institute of Physics.