Abstract
The immersion in HF solutions of silicon containing nanocavities (produced by the annealing at high temperature, 950 degrees C, of silicon implanted with helium at high fluence, 2 X 10(16) cm(-2)) results in the injection of hydrogen in an infrared-mute state (most likely HA into the nanocavities. The pressure achieved in the cavities is sufficiently high to stabilize the hydrogen coverage of the inner surfaces at: temperatures exceeding by 200 degrees C the one of complete desorption from the outer surface.