Resistor integration structure and technique for noise elimination
A method of preventing contact noise in a SiCr thin film resistor includes performing in situ depositions of a SiCr layer and then a TiW layer on a substrate without breaking a vacuum between the depositions, to prevent formation of any discontinuous oxide between the SiCr layer and the TiW layer. The SiCr and TiW layers are patterned to form a predetermined SiCr thin film resistor pattern and a TiW resistor contact pattern on the SiCr thin film resistor, and a metallization layer is provided to contact the TiW forming the resistor contact pattern.
1. A low noise SiCr thin film resistor, comprising:
(a) an SiCr layer; and
(b) a TiW layer disposed on a contact area of the SiCr layer without any discontinuous oxide interface between the SiCr layer and the TiW layer sufficient to cause noiseproducing current-path-shifting of current flowing through both the SiCr layer and the TiW layer.
2. The low noise SiCr thin film resistor of claim 1 including a patterned metallization layer contacting the TiW layer to provide low-noise contact to the SiCr layer.
3. The low noise SiCr thin film resistor of claim 2 wherein the metallization layer is one of the group including aluminum and aluminum alloy.
4. A low noise SiCr thin film resistor made by the method of preventing contact noise comprising:
(a) performing in situ depositions of a SiCr layer and then a TiW layer on a substrate without breaking a vacuum between the depositions, to prevent formation of any discontinuous oxide between the SiCr layer and the TiW layer;
(b) patterning the SiCr and TiW layers to form a predetermined SiCr thin film resistor pattern and a TiW resistor contact pattern on the SiCr thin film resistor; and
(c) depositing and patterning a metallization layer to contact the TiW forming the resistor contact pattern.
5. The low noise SiCr thin film resistor as recited in claim 4 wherein the metallization is composed of one of the group including aluminum and aluminum alloy.
6. The low noise SiCr thin film resistor as recited in claim 4 wherein the method of making includes performing a SiOr stabilization process after the patterning of the metallization layer.
7. The low noise SiCr thin film resistor as recited in claim 4 wherein the method of making includes performing a metallization pre-clean operation before depositing the metallization layer.
8. The low noise SiCr thin film resistor as recited in claim 4 wherein the method of making includes performing a metallization pre-clean operation before depositing the metallization layer, and performing a SiCr stabilization process after the patterning of the metallization layer.
9. The low noise SiCr thin film resistor as recited in claim 8 wherein the metallization is one of the group including aluminum and aluminum alloy and wherein the method of making includes performing a TiW strip process after the SiCr stabilization process and depositing passivation on the wafer after step (c).