Boron depth distributions are reported for MeV implants into silicon through a variety of masking materials. Silicon is implanted with boron through a 0.1-µm-thick layer of thermally grown silicon dioxide. Secondary ion mass spectrometry (SIMS) shows the projected ranges agree within 10% with data reported in the literature and with results from the computer program TRIM. Silicon dioxide, photoresist, and metal layers are used to mask the high-energy boron implants. The SIMS results indicate that TRIM overestimates the energy loss of MeV boron ions as they pass through photoresist and/or silicon dioxide.