Feature Size and Critical Charge

As devices become smaller and faster, they store less charge on circuit nodes, and the energy needed to change the state of a node becomes smaller. Petersen [1996] has noted that critical charge (Q_c) and feature size (t) appear to follow a roughly quadratic relationship given by:

Qc = 0.023 t²

where Q_c is expressed in pC and t in microns. Moreover, this relationship appears to be roughly independent of device technology.

For further information, see

• E.L. Petersen, "Single Event Analysis and Prediction", NSREC Short Course, July 1997.