Transistor Source Region Dislocation for Electron Mobility
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Solution Overview
Problem
The formation of dislocations in the drain region of transistors can lead to increased junction leakage due to voltage differences, which compromises the performance of integrated circuits by reducing electron mobility.
Innovation Solution
A method is developed to form dislocations only in the source region of transistors by creating a mask layer, patterning it to expose the source region, performing ion implantation, and annealing to re-crystallize the semiconductor substrate, thereby increasing electron mobility without increasing junction leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dislocations are formed in the drain region to improve electron mobility, then the driving current increases, but the junction leakage increases
Solution Approach 1:
The patent applies local quality by forming dislocations only in the source region adjacent to the channel, while keeping the drain region free of dislocations. This is achieved through selective ion implantation and annealing processes that create dislocations in specific locations. The source region receives the ion implantation treatment to generate dislocations that induce tensile stress and improve electron mobility, whereas the drain region is excluded from this treatment to avoid junction leakage problems.
2Reliability
If dislocations are formed in the source region to increase electron mobility, then the driving current improves, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the ion implantation and annealing processes into selective steps that affect only the source region. This is accomplished by using masking techniques during ion implantation to protect the drain region while treating the source region. The segmentation allows independent optimization of the source and drain regions, enabling dislocation formation in the source without affecting the drain, thereby improving electron mobility while controlling manufacturing complexity through targeted processing.
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 enhances electron mobility in the channel region while minimizing the risk of junction leakage by isolating dislocations to the source region, thereby improving the performance of transistors without affecting the drain region.
Implementation Method 1
performing a first ion implantation to the exposed portion of the source region
Implementation Method 2
annealing the semiconductor substrate so as to form a dislocation in the exposed portion of the source region
Implementation Method 3
the semiconductor substrate is annealed so as to re-crystallize the amorphous regions
Data Source
AI summary
The present invention relates to a transistor and the method for forming the same. The transistor of the present invention comprises a semiconductor substrate; a gate dielectric layer formed on the semiconductor substrate; a gate formed on the gate dielectric layer; and a source region and a drain region located in the semiconductor substrate and on respective sides of the gate, wherein only the source region comprises at least one dislocation. The method for forming a transistor according to the present invention comprises forming a mask layer on a semiconductor substrate on which a gate has been formed so that the mask layer covers the gate and the semiconductor substrate; patterning the mask layer to only expose at least a portion of a source region; performing a first ion implantation to the exposed portion of the source region; and annealing the semiconductor substrate so as to form a dislocation in the exposed portion of the source region.