Wraparound Backside Contact for Low-Capacitance Semiconductor Junctions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current backside contact schemes in semiconductor devices suffer from high capacitance to the gate and high resistance due to a small silicide area, leading to worsened performance.
Innovation Solution
A method of manufacturing a backside contact involving the formation of an epitaxial structure on a planar substrate, followed by depositing metal on exposed parts of the epitaxial structure to form reacted metal layers. These layers are then selectively removed to create a continuous reacted metal layer around the epitaxial structure, forming a backside contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional backside contact scheme is used, then power distribution is achieved, but capacitance to the gate increases and resistance increases due to small silicide area
Solution Approach 1:
The patent transitions from a planar contact structure to a three-dimensional wraparound structure. The reacted metal layer extends laterally along the epitaxial structure from the backside contact, creating a continuous conductive path that wraps around the structure. This dimensional change increases the effective silicide area without increasing the contact footprint, thereby reducing both capacitance to gate and resistance.
Solution Approach 2:
The patent merges the backside contact structure with the frontside silicide by creating a continuous reacted metal layer that connects both regions. This integration eliminates the need for separate contact structures and reduces the number of interfaces, thereby reducing capacitance and resistance while maintaining reliable power distribution.
2Reliability
If a conventional backside contact scheme is used, then power distribution is achieved, but resistance increases due to small silicide area
Solution Approach 1:
The patent transitions from a planar contact structure to a three-dimensional wraparound structure. The reacted metal layer extends laterally along the epitaxial structure from the backside contact, creating a continuous conductive path that wraps around the structure. This dimensional change increases the effective silicide area without increasing the contact footprint, thereby reducing both capacitance to gate and resistance.
Solution Approach 2:
The patent merges the backside contact structure with the frontside silicide by creating a continuous reacted metal layer that connects both regions. This integration eliminates the need for separate contact structures and reduces the number of interfaces, thereby reducing capacitance and resistance while maintaining reliable power distribution.
3Reliability
If top contact metal is present, then electrical connection is achieved, but capacitance to the gate increases
Solution Approach 1:
The patent removes the top contact metal structure entirely, extracting the harmful capacitive element from the system. Instead, the electrical connection is achieved through the wraparound reacted metal layer that provides a low-capacitance path from the backside contact to the epitaxial structure, eliminating the need for top contact metal.
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 approach reduces capacitance and resistance to the gate, improving the overall performance of the semiconductor device by fully wrapping the junction with reacted metal and eliminating the need for a top contact metal.
Implementation Method 1
depositing a metal on the second part and the body portion of the epitaxial structure, whereby to form a first reacted metal layer
Implementation Method 2
The backside silicidation process merges with the frontside silicide, achieving a metal contact between the frontside silicide and the backside silicide
Data Source
Figure 1
Figure 2
Figure 3a~3k
AI summary
In some examples, a method of manufacturing a backside contact comprises providing an epitaxial structure on a planar substrate, wherein the epitaxial structure comprises a first part adjacent to a first surface of the planar substrate, a body portion, and a second part separated from the first part by the body portion such that the second part and the body portion are exposed above the first surface of the planar substrate, depositing a metal on the second part and the body portion of the epitaxial structure, whereby to form a first reacted metal layer on the second part and the body portion of the epitaxial structure, selectively removing unreacted metal from at least a portion of the first surface of the planar substrate, selectively removing a portion of the substrate on a second surface of the planar substrate to expose the first part of the epitaxial structure, wherein the second surface of the planar substrate is opposite to the first surface of the planar substrate, depositing a metal on the first part of the epitaxial structure, whereby to form a second reacted metal layer on the first part of the epitaxial structure, wherein the first reacted metal layer and the second reacted metal layer form a continuous reacted metal layer around the epitaxial structure, selectively removing unreacted metal from at least a portion of the second surface of the planar substrate, and forming the backside contact on a portion of the second reacted metal layer.