It is found that shallow hydrogen-related donors are formed in the proton-implanted dilute Ge(1-x)Si(x) alloys (0 <= x <= 0.031) as well as in Si-free Ge samples upon heat-treatments in the temperature range 225-300 degrees C. The maximum concentration of the donors is about 1.5 x 10(16) cm(-1) for a H(+) implantation dose of 1 x 10(15) cm(-2). The temperature range of formation of the proton-implantation-induced donors is the same in Ge(1-x)Si(x) samples with a different Si concentration. However, the increase in Si content results in a decrease of the concentration of the H-related donors. The possible origin of the H-related donors and mechanisms of Si-induced suppression of their formation are discussed. (C) 2008 Elsevier B.V. All rights reserved.