Collision cascade mixing in the sputter depth profiling process broadens the measured width of abrupt dopant structures by displacing the target atoms, predominantly through collisions with the disturbed matrix atoms prior to sputter removal. Sputtering theory predicts a profile broadening dependence on the nuclear stopping power of the projectile in the target matrix, but this is not supported by experimental data. In this experiment, abrupt boron profiles were measured in a matrix of silicon or germanium, at a range of energies from 2.5 to 10.5 keV The higher mass matrix gives access to high stopping powers, particularly for Xe+ projectiles. As with the projectile mass experiments, this work does not support the predicted change in decay length with the range of the projectile. The data indicate the decay length dependence on projectile energy alone is due to dopant displacements by primary recoils as well as the collision cascade mixing.