The etching effects of hydrogen plasma for semiconductor materials including single crystalline silicon, polycrystalline silicon, silicon dioxide, and aluminum in plasma immersion ion implantation (PHI) doping experiments have been investigated. Etching can alter device structure and affect implant profile and dose. The effects of varying different PIII process parameters such as pulse potential, pulse repetition frequency, and substrate temperature are presented. The experimental data show that the spontaneous etching by hydrogen radicals enhanced by ion bombardment is responsible for the etching phenomena that occurs at the material surface. A model is used to calculate the retained implant dose and impurity profile when the etching effect is considered.