Effects of low-energy back surface gettering on the properties of 1/f noise in n-channel nitrided MOSFETs

Abstract

Flicker noise in backsurface gettered, nitrided n-channel MOSFETs is characterized over a wide range of temperatures and biases. The gettering time ranged from 10 to 40 minutes. The noise power spectra for devices with different gettering times are compared to the ungettered devices which serve as the control. It is found that flicker noise is reduced by backsurface gettering for short gettering times. A rebound in the noise magnitude is observed for long gettering times. Investigations of the temperature dependencies of the noise power spectra indicates that the low-frequency noise arises from thermal activation of carriers to traps at the Si-SiO2 interface. Back-surface gettering results in the modification of the energy distribution of the interface traps, probably due to stress relaxation at the Si-SiO2 interface.