Dummy Gate Structure for SRAM Leakage Prevention
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Solution Overview
Problem
Current semiconductor manufacturing processes face issues with leakage current in SRAM devices due to N+ ion implantation, where the photoresist shrinks, exposing P+ doped regions, leading to dopant intrusion and voltage differences between the source and drain of PMOS transistors, resulting in current leakage.
Innovation Solution
A semiconductor device and manufacturing method that includes a dummy gate electrically connected to a first doped region, with a trench isolator portion and well region, and connecting members to prevent current leakage by ensuring the transistor is turned off, using conductivity type doped regions and connecting members to manage voltage effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist is used to block P+ doped regions during N+ ion implantation, then doping selectivity is improved, but photoresist shrinkage exposes P+ regions leading to dopant intrusion and current leakage
Solution Approach 1:
A dummy gate structure is formed beforehand in the dummy cell portion before ion implantation. This dummy gate serves as a preliminary protective structure that prevents N+ dopant intrusion into P+ source regions during subsequent doping processes, eliminating the need for photoresist blocking and avoiding the shrinkage problem entirely.
Solution Approach 2:
The dummy gate structure acts as an intermediary element between the ion implantation process and the P+ doped regions. It physically blocks the N+ dopants from reaching the P+ source regions during implantation, serving as a mediator that protects the sensitive regions without requiring photoresist materials.
2Device complexity
If N+ ion implantation is performed without adequate blocking, then manufacturing complexity is reduced, but P+ doped regions are exposed leading to dopant intrusion and device malfunction
Solution Approach 1:
The dummy gate structure is formed as a preliminary feature before ion implantation occurs. This pre-formed structure provides automatic geometric blocking during the implantation process, maintaining doping precision without adding complex photoresist patterning steps or multiple alignment procedures.
3Manufacturing precision
If photoresist is used for blocking during ion implantation, then doping control is improved, but photoresist shrinkage causes exposure and leakage current
Solution Approach 1:
The dummy gate structure serves as a permanent intermediary blocking element during ion implantation. Unlike photoresist that shrinks and fails, the dummy gate is a stable structural feature that maintains its blocking function throughout the process, preventing both dopant intrusion and the generation of leakage current.
Solution Approach 2:
The dummy gate structure, which might seem like an unnecessary addition, actually converts the potential harm of dopant intrusion into a benefit by providing robust geometric blocking. The presence of this extra structure prevents the harmful effect of N+ dopant intrusion into P+ regions, eliminating leakage current paths.
4Reliability
If dummy gate structure is added to prevent leakage, then reliability is improved, but device structure complexity increases
Solution Approach 1:
The dummy gate structure serves multiple functions simultaneously: it acts as a blocking barrier during ion implantation, defines the boundary of the dummy cell portion, and prevents dopant intrusion into adjacent P+ regions. By consolidating these functions into a single structure, the actual increase in complexity is minimized while achieving reliable leakage prevention.
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 solution effectively prevents current leakage in SRAM devices by ensuring the transistor is turned off, thereby improving the reliability of the memory device by managing dopant concentrations and voltage connections.
Implementation Method 1
performing a first ion implantation into the substrate structure to form a first doped region
Data Source
AI summary
A method for manufacturing semiconductor devices is provided. The method includes: providing a substrate structure comprising a semiconductor substrate and a trench insulator portion in the semiconductor substrate; forming a dummy gate on the semiconductor substrate; performing a first ion implantation into the semiconductor substrate to form a first doped region between the trench insulator portion and the dummy gate; and forming a first connecting member connecting the dummy gate with the first doped region.