Source/Drain Contact Trench Dielectric Liner for Lower Capacitance
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Solution Overview
Problem
As the pitch between adjacent transistors scales downwards, gate-to-contact capacitance increases, and the contact area between the contact metal and the source/drain material decreases, leading to increased contact resistance and potential short circuits due to wide trench widths in source/drain contacts.
Innovation Solution
Incorporating a dielectric liner within the source/drain contact trench and on top of the contact metal structure, with an additional dielectric liner on the outside, to enhance the contact area and reduce parasitic capacitance, thereby improving yield and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pitch between adjacent transistors is scaled downwards, then the transistor density is improved, but the gate-to-contact capacitance increases and the contact area decreases leading to increased contact resistance
Solution Approach 1:
The patent introduces a vertical dielectric liner structure within the contact trench, adding a dimensional element that separates the contact metal from the gate vertically. This vertical separation reduces the parasitic capacitance between gate and contact while maintaining the scaled-down pitch, thus improving transistor density without compromising contact reliability
Solution Approach 2:
The dielectric liner acts as an intermediary material placed between the contact metal and the gate structure. This intermediate layer reduces the direct capacitive coupling between the contact and gate, thereby reducing parasitic capacitance and improving signal integrity while allowing closer spacing for higher density
Data Source
AI summary
An integrated circuit device comprising at least one first layer at a bottom of a trench, the at least one layer connecting to a source/drain region of a transistor, the at least one layer comprising metal; a second layer on the at least one first layer, the second layer comprising metal; and a third layer on the at least one first layer and within the trench, the third layer comprising a dielectric material.