  A study is presented of the structural changes occurring as a function of the
annealing conditions in hydrogenated amorphous Si/Ge multilayers prepared by
sputtering. Annealing changes the structure of the as-deposited multilayer
except for the less severe conditions here applied (150 oC, time<22 h). For
higher temperatures and/or times, the modifications consist of layer
intermixing and surface degradation in the shape of bumps and craters. They are
argued to be due to the formation of H bubbles upon heating. Hydrogen should be
mostly released from the amorphous Ge layers.
