BACK AND FRONT INTERFACE RELATED GENERATION-RECOMBINATION NOISE IN BURIED-CHANNEL SOI PMOSFETS

This paper reports on a detailed study of generation-recombination (GR ) noise in buried-channel Silicon-on-Insulator (SOI) pMOSFET's, occurr ing in the linear operation mode. In particular, the plateau amplitude and the corner frequency (relaxation time tau) Of the Lorentzian are investigated as a function of the front (V-Gf) and of the back gate bi as (V-Gb) It is shown that different cases can be distinguished, depen ding of the conduction mode of the device, i,e. for surface or buried channel operation. For surface channel operation the GR noise paramete rs are strongly influenced by the back gate bias and only weakly depen dent on V-Gf The opposite is true when the front interface starts to d eplete, thereby pushing the channel deeper into the Si film. As is sho wn, the relaxation time depends exponentially on either V-Gf or V-Gb A Similar exponential gate-bias dependence is found for the Lorentzian amplitude. Based on the observations, it is concluded that the GR nois e originates from the front or the back interface, depending on the op eration mode. The effective density of front and back interface traps can be derived from the GR noise amplitude.