Current crowding and its effect on 1/f noise and third harmonic distortion -: a case study for quality assessment of resistors

In this paper, we discuss the impact of current crowding on 1/f noise generation and third harmonic distortion in semiconductor devices. We propose a model for the 1/f noise in resistors taking into account the effect of current crowding. This model can be applied to devices that suffer from current crowding due to e.g., multiple spot contacts on homogeneous samples, inter-grain contacts in polysilicon or poly SiGe resistors, grain contacts in thick-film resistors or non-homogeneous thin films and nano particle contacts. The model shows that current crowding has a much larger effect on the 1/f noise of a device than on its resistance. Current crowding at multi-spot contacts also increases the local temperature due to the small value of thermal time constants of multi-spot contacts and increases the contact resistance. This results in third harmonic distortion. Our model explains qualitatively that an increase in 1/f noise goes hand in hand with an increase in third harmonic distortion. (C) 2000 Elsevier Science Ltd. All rights reserved.