Estimation of doping profiles in short channel MOSFET's using DC Measurements

Estimation of impurity profiles in short channel enhancement-mode MOSFET's using the dc measurement technique is studied. The use of long channel theory predicts erroneous impurity profiles for devices with channel lengths of less than 6 µm. A new empirical model for substrate charge sharing is presented which provides good agreement between profiles estimated by measurements on identically doped long and short channel MOSFET's. It is found that the dc measurement technique can be extended to enhancement-mode MOSFET's with channel lengths as small as 2.5 µm.