Chemical bonding changes and electrical effects of hydrogen implantation into silicon nitride have been investigated. Silicon nitride films were prepared by chemical vapor deposition from the decomposition products of and gases onto silicon substrates at 850°C. Implantation of either hydrogen or deuterium causes Si‒H bond formation by transferring deposition‐incorporated hydrogen from nitrogen to silicon bonds. The implanted hydrogen isotope, however, bonds predominantly on nitrogen. Displacement damage, which causes the N‐H band to broaden and shift to lower frequencies, is reduced by annealing at 500°C, and a loss of both N‒H and Si‒H bonds occurs when implanted films are annealed at temperatures >500°C. The observed electrical effects of hydrogen implantation of silicon nitride followed by annealing at 500°C are increased equilibrium positive charge, decreased charge transport, and enhanced charge trapping and retention. A correlation between deep traps and Si‒H bond formation in silicon nitride is suggested to explain the electrical effects.