Reverse-biased silicon p-n junction arrays have been proposed as microdosimetry detectors. The tissue equivalence of such detectors in boron neutron capture therapy (BNCT) is discussed. A comparison of the range-energy relationships of H, He, C, and Li ions in tissue (ICRU-muscle) and silicon is given. A simple geometrical scaling (approximately 0.63) of linear dimensions is required to convert microdosimetric energy deposition measurements performed in silicon to equivalent deposition in tissue. The Monte Carlo technique is used to examine energy deposition for two simple geometrical cases applicable to BNCT.