US 9,000,564 B2 · Precision polysilicon resistors

Abstract

Use of a replacement metal gate (RMG) process provides an opportunity to create precision polysilicon resistors alongside metal gate transistors. During formation of a sacrificial polysilicon gate, the precision polysilicon resistor can also be formed from the same polysilicon film. The polysilicon resistor can be slightly recessed so that a protective insulating layer can cover the resistor during subsequent replacement of the sacrificial gate with a metal gate. The final structure of the precision polysilicon resistor fabricated using such a process is more compact and less complex than existing structures that provide metal resistors for integrated circuits having metal gate transistors. Furthermore, the precision polysilicon resistor can be freely tuned to have a desired sheet resistance by either implanting the polysilicon film with dopants, adjusting the polysilicon film thickness, or both.

Claims20

Dependent claims

A precision polysilicon resistor structure comprising:

a silicon substrate having an upper surface;
an isolation field formed in the silicon substrate, the isolation field filled with an oxide in contact with, and adjacent to, a metal gate transistor, the oxide recessed relative to the upper surface of the silicon substrate;
a precision polysilicon resistor overlying, and in contact with, the filled isolation field;
conformal insulating layer overlying, covering, and in contact with, both a top surface and a side surface of the polysilicon resistor;
an inter-layer dielectric;
and
one or more metal plugs that extend into the inter-layer dielectric to make ohmic contact with the polysilicon resistor at a metal-polysilicon junction.

4 more elements

Dependencies are inferred from the claim text.

Precision polysilicon resistors

Life of this patent

Precision polysilicon resistors

Life of this patent

Abstract

Claims20