  Hydrogen loss from a-SiNx:H films under irradiation with 100 MeV Ag7+ ions
using elastic recoil detection analysis (ERDA) experiments is reported. The
results are explained under the basic assumptions of the molecular
recombination model. The ERDA hydrogen counts are composed of two distinct
hydrogen desorption processes, limited by rapid molecular diffusion in the
initial stages of irradiation, and as the fluence progresses a slow process
limited by diffusion of atomic hydrogen takes over. Which of the aforesaid
processes dominates, is determined by the continuously evolving Hydrogen
concentration within the films. The ERDA measurements were also carried out for
films treated with low temperature (300 degrees centigrade) hydrogen plasma
annealing (HPA). The HPA treated films show an improved diffusion of atomic
hydrogen, resulting from healing of weak bonds and passivation of dangling
bonds. Further, upon HPA, films also show evolution of hydrogen with
significantly higher counts, at advanced fluences, relative to the as-deposited
films. These results indicate the potential of HPA towards improved H retention
in a-SiNx:H films. The study distinguishes clearly the presence of two
diffusion processes in a-SiNx:H whose diffusion rates differ by an order of
magnitude, with hydrogen radicals not being able to diffuse beyond ~1 nm from
the point of their creation. The results are very relevant for the passivation
applications of a-SiNx:H
