A method for evaluating characteristics of a plasma or the effects of the plasma on a substrate includes introducing a plasma probe into a reaction chamber. The plasma probe may be introduced into the chamber with or without a substrate. The plasma probe is exposed to substantially the same conditions to which the substrate is, has been, or will be exposed. The plasma probe may include features that represent corresponding features on the substrate. One or more characteristics of the plasma, or its effects on the plasma probe, may be evaluated at one or more locations on the plasma probe.