Low-frequency noise behavior of La-doped HfSiON/metal gate nMOSFETs

We investigate the low-frequency noise characteristics of HfSiON/metal gate nMOSFETs with and without La-doping and report new findings on the impact of La-doping on low-frequency noise of the nMOSFETs. The La-doped devices show lower noise intensity than the un-doped devices and it is attributed to the reduced trap density (N_t) and tunneling attenuation length (λ) caused by the La-doping. In the case of submicron devices, however, the La-doped devices show additional mobility-fluctuation noise at low-field condition and the additional noise intensity increases as the gate length decreases. These results indicate that the advantage of low noise of La-doping technique can decrease or even disappear in case of short-channel devices used for analog applications.