The sensitivity in the determination of deuterium and15N by nuclear reactions was examined for the following reactions: (1)15N(d,n)16O (or p+)+(6.13, 7.11 MeV); (2) D(3He,)4He (13 MeV); and (3)15N(,n)18F. By these activations with suitable etching techniques, sub ppm regions of D and15N have proved to be measurable with their depth profiles. Some fundamental properties of hydrogen and nitrogen in silicon are under investigation using of these activable tracers.