Temperature dependence of scattering in the inversion layer

Electron mobility has been measured in the silicon inversion layers of devices whose gate oxides were deliberately contaminated with Na+ ions. The mobility was measured as a function of inversion layer carrier density (1.0 × 1012 ⩽ NINV ⩽ 1.2 × 1013 cm−2), interfacial Na+ ion density (8.3 × 1010 ⩽ NOX ⩽ 2.02 × 1012 cm−2), substrate bias voltage (−15 ⩽ Vsub ⩽ +0.5 V) and temperature (4.2 ⩽ T ⩽ 80 K). From the data it is possible to separate the contributions to the mobility arising from ionized impurity scattering, surface roughness scattering and phonon scattering. The surface roughness scattering was found to be independent of temperature. The ionized impurity scattering was found to have components due to both single and multiple scattering processes, each of which were temperature dependent. Below 32 K there was no measureable phonon scattering. © 1980, All rights reserved.