Precision polysilicon resistors

A method of fabricating a precision polysilicon resistor structure adjacent to a metal gate transistor, the method comprising:

• forming isolation regions in a silicon substrate, the isolation regions including an isolation field;
• filling the isolation regions with an oxide, the oxide being in contact with an adjacent active area of silicon;
• recessing the oxide within the isolation field to a selected recess depth below a surface of the silicon substrate;
• forming a polysilicon resistor and a sacrificial polysilicon gate from a common conformally deposited polysilicon film, the polysilicon resistor overlying, and in contact with, the recessed isolation field;
• forming a protective insulator over the polysilicon resistor and the adjacent active area of silicon;
• replacing the sacrificial polysilicon gate with a metal gate;
• depositing an inter-layer dielectric over the metal gate transistor and the precision polysilicon resistor;
• and
• forming electrical contacts to the metal gate transistor and the precision polysilicon resistor through the inter-layer dielectric.

An integrated circuit comprising:

• a silicon substrate;
• a replacement metal gate transistor formed in the silicon substrate, the transistor including:
• one or more isolation trenches;
• source and drain regions;
• and
• a replacement metal gate;
• and
• at least one polysilicon resistor adjacent to the replacement metal gate transistor, the polysilicon resistor formed over a recessed isolation field.