Defect levels produced by low‐dose H+bombardment of silicon with different phosphorus doping and oxygen content were investigated using transient capacitance spectroscopy. For vacancy‐related defects both the peak concentration and the half width of defect profiles depend only on the position of the Fermi energy. All defect profiles were found to be broader than the theoretical vacancy distribution. The broadening which increases with decreasing doping level is explained by a model based on electric‐field‐enhanced diffusion.