Polysilicon resistor trimming for packaged integrated circuits

Abstract

Pulse current trimming to adjust values of polysilicon resistors has been investigated for use in full scale IC production. The technique is remarkably accurate, layout efficient, quick and inexpensive from a test perspective, and requires no additional process complexity. The trim process is shown to be reversible to a small, but usable extent for n-type polysilicon. A new physical model consistent with all observations for resistance trim and recovery is presented. Finally, reliability results from extensive burn-in show the trimmed resistors to be exceptionally robust.<>