We have employed Mossbauer spectroscopy and low H implantation to stud
y the Sb-H complexes in n-type Si. The different Mossbauer components
were studied as a function of H dose, H-implantation temperature, and
annealing temperature. To understand the observed data, it is necessar
y to introduce, in addition to the well-known SbH complex, an SbH(n) c
omplex (n greater-than-or-equal-to 2), which provides experimental evi
dence for the existence of donor-multihydrogen complexes. We show that
these complexes are in thermal equilibrium with a larger hydrogen res
ervoir (H-2), which governs their thermal stability.