Strained Nitride Recess in Semiconductor Structure for Drive Current
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Solution Overview
Problem
Conventional MOSFET semiconductor devices face issues with reduced drive current and increased leakage due to the close proximity of metal silicide to the PN junction, which damages the lattice structure and affects the effectiveness of the transistor.
Innovation Solution
A semiconductor device structure is developed with a silicide substrate, a nitride layer, and a strained nitride coating, where the nitride layer and shallow trench isolation areas form a recess with an etching space larger than the recess, increasing the channel distance and promoting efficient electron hole mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal silicide is located at the silicide substrate in self-aligned silicide fabrication, then the manufacturing process is simplified, but the lattice structure of the source and drain areas is damaged and leakage increases
Solution Approach 1:
The patent extracts the metal silicide from direct contact with the source/drain regions by introducing a recess structure. The silicide is positioned in a recess that is separated from the source/drain areas, eliminating the harmful interaction while preserving the self-aligned fabrication benefits.
Solution Approach 2:
The patent introduces an intermediary recess structure between the metal silicide and the source/drain regions. This recess acts as a mediator that prevents direct contact, thereby protecting the lattice structure and preventing leakage while allowing the silicide to remain in its beneficial position for simplified manufacturing.
2Speed
If epitaxial layer is formed in recesses to increase electron hole mobility, then carrier mobility is improved, but the polysilicon wire width of the gate becomes insufficient and drive current decreases
Solution Approach 1:
The patent applies local quality by forming the epitaxial layer only in specific localized recesses rather than throughout the entire gate structure. This allows the mobility-enhancing epitaxial layer to be present only where needed (in the source/drain regions) while preserving the full polysilicon gate width for optimal drive current.
Solution Approach 2:
The patent segments the structure by creating discrete recesses in the source and drain regions rather than a continuous modification. This segmentation allows the epitaxial layer to be formed in isolated areas to improve mobility without affecting the overall gate structure and drive current.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The strained nitride coating enhances electron hole mobility and increases drive current while reducing leakage, thereby improving the operating efficiency of the semiconductor device.
Implementation Method 1
the strained nitride coating could change the distance between two Silicon atoms of the two doping areas and increase the electron hole mobility
Data Source
AI summary
A semiconductor device is disclosed which includes a silicide substrate, a nitride layer, two STIs, and a strain nitride. The silicide substrate has two doping areas. The nitride layer is deposited on the silicide substrate. The silicide substrate and the nitride layer have a recess running through. The two doping areas are at two sides of the recess. The end of the recess has an etching space bigger than the recess. The top of the silicide substrate has a fin-shaped structure. The two STIs are at the two opposite sides of the silicide substrate (recess). The strain nitride is spacer-formed in the recess and attached to the side wall of the silicide substrate, nitride layer, two STIs. The two doping areas cover the strain nitride. As a result, the efficiency of semiconductor is improved, and the drive current is increased.