OXYGEN RESERVOIR FOR LOW Vth PFET
AssigneeInternational Business Machines Corporation
InventorsTakashi Ando, Choonghyun Lee, Jingyun Zhang
Life of this patent
Estimating the term…
Abstract
A p-type FinFET has an oxygen reservoir disposed on the gate stack. The oxygen reservoir provides an oxygen rich environment during processing steps of manufacturing the device to help the work function metal retain or obtain oxygen to maintain or increase the work function and keep the Vth of the device lower.
Claims20
A p-type FinFET comprising:
- a channel;
- a source electrically connected to a source side of the channel;
- a drain electrically connected to a drain side of the channel;
- a gate stack comprising a high k dielectric material disposed on the channel and a work function metal disposed on the high k dielectric material;
- an oxygen reservoir disposed on the gate stack, the oxygen reservoir made of a reservoir material, the reservoir material containing oxygen, the oxygen reservoir having a top surface;
- and
- a metal layer directly connected to the top surface.
The p-type FinFET, as in claim 11, where the channel is made of Silicon (Si).
The p-type FinFET, as in claim 11, where the reservoir material is one of:
- Silicon Dioxide (SiO2) and Silicon Oxynitride (SiON).
The p-type FinFET, as in claim 11, where the work function metal (WFM) is one of:
- Titanium Nitride (TiN), Titanium Oxynitride (TiON), Tantalum Nitride (TaN), and Tantalum Oxynitride (TaON).
The p-type FinFET, as in claim 11, where the work function metal (WFM) is formed with layers of two or more deposition layers.
The p-type FinFET, as in claim 11, where a top of the oxygen reservoir is recessed below a top surface of the replacement metal gate.
The p-type FinFET, as in claim 11, where the work function metal has an effective work function (EWF) of 5.0 electron Volts (eV) or greater.
A p-type FinFET comprising:
- a channel;
- a source electrically connected to a source side of the channel;
- a drain electrically connected to a drain side of the channel;
- a gate stack comprising a high k dielectric material disposed on the channel and a work function metal (WFM) disposed on the high k dielectric material;
- an oxygen reservoir disposed on the gate stack, the oxygen reservoir made of a reservoir material, the reservoir material containing oxygen;
- and
- a low resistivity metal layer contact electrically connected to the work function metal (WFM) as well as being physically disposed above a top of the oxygen reservoir.
A method of making a p-type FinFET, comprising the steps of:
- forming a gate trench between a first and second spacer disposed on a fin,
- forming a source on a source side of the first spacer and a drain on a drain side of the second spacer, a channel being a region of the fin between the first and second spacer;
- depositing a high-k dielectric within the gate trench on the channel and on one side of each of the spacers exposed within the gate trench;
- depositing a work function metal (WFM) on the high-k dielectric to form a gate stack above the channel;
- depositing an oxygen reservoir on the gate stack;
- and
- depositing a low resistivity metal layer contact electrically connected to the work function metal as well as being physically disposed above a top of the oxygen reservoir.
Dependencies are inferred from the claim text.