A simple method to characterize substrate current in MOSFET's

Experimental verification of substrate current characteristics is thoroughly carried out. V
DS
- V
DSAT
, instead of V
DS
, is shown to be the driving force of all hot-electron effects. A simple relationship between substrate current and V
DS
- V
DSAT
is found. This relationship provides a convenient tool to characterize the substrate current or the channel electric field, and, hence, all hot-electron effects. Measurements of I
SUB
/I
D
and V
DS
- V
DSAT
at two bias points and any one channel length are sufficient to fully characterize the substrate currents for all channel lengths V
DS
's and V
G
's for a given technology.