This letter investigates the effect of the substrate bias on the capture kinetics of random telegraph signals in submicron siliconp‐channel metal–oxide–semiconductor transistors. A strong dependence of the capture time constant &tgr;con the transverse electric field is observed. As a result, &tgr;c∼exp(−Ap) is observed experimentally, which is much stronger than the 1/pdependence predicted by simple Shockley–Read–Hall theory, wherebypis the surface density of free holes. The observations are explained tentatively by considering a field‐dependent hole capture cross section. The latter may result from quantization effects induced by the transverse field in the two‐dimensional inversion layer. ©1995 American Institute of Physics.