Depletion compensated polysilicon electrodes
AssigneeMicron Technology, Inc.
InventorsRavi Iyer, Luan Tran, Charles L. Turner
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Abstract
A capacitor in a semiconductor integrated circuit is fabricated having a fixed charge density introduced near an electrode/dielectric interface. The fixed charge density compensates for the effects of a depletion layer, which would otherwise lower the effective capacitance. By shifting the undesirable effect of the depletion capacitance outside of the operating voltage range, the capacitor is effectively converted to an accumulation mode. The fixed charge density is preferably introduced by a plasma nitridation process performed prior to formation of the capacitor dielectric.
Claims7
A capacitor in an integrated circuit designed to operate within a first range of applied voltages, the capacitor comprising:
- first and second conducting electrodes;
- an insulating layer interposed between the first and second conducting electrodes, wherein the first electrode develops a depletion region such that the capacitor experiences a drop-off in capacitance when operated within a second range of applied voltages, wherein the first electrode includes a layer of charged material disposed adjacent the insulating layer so as to modify the capacitance vs. voltage behavior of the capacitor such that the second range is displaced with respect to the first range, thereby decreasing the variation in the capacitance of the capacitor when the capacitor is operated within the first range of applied voltages.
Dependencies are inferred from the claim text.