Charging and discharging properties of electron traps created by hot-carrier injections in gate oxide of n-channel metal oxide semiconductor field effect transistor

Abstract

The charging and discharging properties of electron traps created by hot-carrier injections in the thin gate oxide of n-channel metal oxide semiconductor transistors are analyzed by means of the effects that charge state transitions induce on the low-level gate current (lower than 1 pA) of the transistor. This current is measured by a very senstive floating-gate technique [F.H. Gaensslen and J.M. Aitken, IEEE Electron. Device Lett. EDL-1, 231 (1980)]. Two traps with electron capture cross sections of the order of 10−14 and 10−15 cm2 are analyzed which are linked with optical and field-dependent measurements of electron emission properties. Thermal and optical ionization energies of these defects are determined at ≊1.7±0.2 and ≊3.0±0.5 eV, respectively. Comparison with theory suggests that Si dangling bonds or oxygen vacancy in the oxide should be the defects created by hot-carrier injections.