Reverse Dopant Implantation for FinFET Electrical Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Diffusion breaks in semiconductor finFETs lead to structural variability and high current leakage, resulting in device performance degradation due to the need for dielectric formation and fin cut/openings.
Innovation Solution
An electrical isolation structure is formed using a semiconductor fin with a second dopant of opposing polarity between source/drain regions of adjacent fin transistors, extending to the upper surface, eliminating the need for dielectric materials and fin cut/openings, thereby reducing structural variability and current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffusion breaks with dielectric materials are used to isolate finFETs, then electrical isolation between adjacent fins is achieved, but structural variability increases and current leakage occurs
Solution Approach 1:
The patent changes the physical and chemical parameters of the isolation structure by using heavily doped semiconductor regions instead of dielectric materials. The reverse polarity dopant creates a depletion region that provides electrical isolation through parameter control (doping concentration, carrier density) rather than through material composition changes, thereby reducing structural variability while maintaining isolation effectiveness.
Solution Approach 2:
The patent replaces the mechanical/dielectric isolation system (physical separation using dielectric materials) with an electrical/isolation system based on doping. Instead of using physical barriers (dielectrics) to prevent current flow, the invention uses electrical field control through reverse dopant implantation to create a depletion region that blocks current, substituting a mechanical approach with an electrical one.
2Reliability
If diffusion breaks are used to isolate finFETs, then electrical isolation is achieved, but current leakage increases
Solution Approach 1:
The patent controls the electrical parameters of the isolation region by adjusting the dopant concentration and polarity. The heavily doped region with reverse polarity creates a wide depletion region with high electrical resistance, parameter-optimizing the isolation to block leakage currents effectively while maintaining precise control over the isolation characteristics through doping parameters.
3Reliability
If dielectric materials are used for diffusion breaks, then electrical isolation is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the dielectric materials from the isolation structure, removing the need for depositing, patterning, and planarizing dielectric layers. By taking out the dielectric component and replacing it with a doping-based isolation mechanism, the manufacturing process is simplified while maintaining electrical isolation functionality.
Solution Approach 2:
The isolation structure becomes self-forming through the doping process itself. The reverse dopant implantation automatically creates the isolation regions during the doping step, eliminating the need for separate dielectric formation and patterning steps. The structure serves its own isolation function through the doping process rather than requiring additional manufacturing steps.
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
This approach provides effective electrical isolation within the semiconductor fin without dielectrics, maintaining device performance and reducing cycle time by avoiding stress changes and structural issues associated with fin cut/openings.
Implementation Method 1
doping the semiconductor fin in the region between one of the first pair of source/drain regions and one of the second pair of source/drain regions with a second dopant of an opposing, second polarity
Implementation Method 2
electrical isolation structure using reverse dopant implantation from source/drain region in semiconductor fin
Data Source
AI summary
A structure includes a semiconductor fin on a substrate. A first fin transistor (finFET) is on the substrate, and a second finFET is on the substrate adjacent the first finFET. The first finFET and the second finFET include respective pairs of source/drain regions with each including a first dopant of a first polarity. An electrical isolation structure is in the semiconductor fin between one of the source/drain regions of the first finFET and one of the source/drain regions for the second FinFET, the electrical isolation structure including a second dopant of an opposing, second polarity. The electrical isolation structure extends to an upper surface of the semiconductor fin. A related method is also disclosed.