We have investigated the hydrogen termination of p(+)-Si(100) surfaces treated with a dilute hydrofluoric acid solution after hydrogen plasma is used to deactivate the dopant. The carrier concentration of hydrogenated p(+)-Si is reduced by an order of magnitude by this hydrogen passivation but it can be largely restored simply by thermal annealing at moderate temperatures. Contact angle measurement and thermal desorption spectroscopy revealed that the hydrogenated p(+)-Si surface is efficiently terminated by hydrogen in HF solutions and that the H-terminated surface is more stable in water than the original p(+)-Si surface is. The hydrogenated p(+)-Si surface reacts with HF solutions in ways quite similar to these in which a p(-)-Si surface does. On the other hand, the hydrogenation does not affect the HF treatment properties of n(+)-Si. This hydrogen-plasma passivation enables us to obtain a clean H-terminated p(+)-Si surface by using the conventional dilute HF treatments.