Understanding of the temperature dependence of channel hot-carrier degradation in the range 77 K to 300 K

The mechanisms of the enhanced degradation of the n-MOSFET current after low-temperature hot-carrier stress are investigated. It is found that the enhanced electron trapping at low temperatures can only explain a small fraction of this enhanced degradation. The generation of D/sub it/ is shown to decrease at low temperatures. The enhanced degradation at low T is therefore not due to increased interfacial damage. It is shown to be caused by the greater influence of the local hot-carrier-induced damage on the transistor characteristics at low T, due to the dramatic reduction of the thermionic emission process that controls the channel current. In p-MOSFETs, however, the hot-carrier degradation is due to channel shortening effects, which are not governed by the thermionic emission process. The degradation is therefore not highly dependent on temperature in this case.<>