GLDD Implant Structure for Breakdown Voltage in Short-Gate MOSFETs
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Solution Overview
Problem
As integrated-circuit miniaturization progresses, the breakdown voltage (BV) of semiconductor devices decreases, leading to reduced scalability and increased punch-through current, which affects the performance of high-voltage NMOS and PMOS devices.
Innovation Solution
The implementation of breakdown-enhancement implant (BEI) intrusions within gated, lightly doped drain (GLDD) structures, which are strategically positioned to adjust the breakdown voltage and reduce punch-through current by altering the electrical field distribution, thereby maintaining or improving device performance at reduced geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If integrated-circuit miniaturization is pursued to reduce device dimensions, then device density and integration are improved, but breakdown voltage decreases and punch-through current increases
Solution Approach 1:
The patent introduces BEI intrusions with specific doping types and concentrations at localized positions within the LDD regions, creating non-uniform doping profiles that specifically enhance breakdown voltage at critical locations without affecting overall device dimensions. This local modification allows miniaturization to proceed while maintaining high-voltage characteristics in specific areas.
Solution Approach 2:
The patent modifies the electrical field distribution by introducing BEI intrusions with different doping concentrations and types, changing the physical parameters of the semiconductor structure. These parameter changes (doping concentration, doping type, intrusion depth) directly affect the breakdown voltage characteristics, allowing the device to maintain high breakdown voltage despite reduced dimensions.
2Length of moving object
If gate length is reduced for miniaturization, then device scaling is improved, but punch-through current increases
Solution Approach 1:
BEI intrusions are positioned at specific locations within the LDD regions, closer to the channel than the N+ S/D regions, creating localized doping enhancements that specifically address punch-through current at the channel interface without affecting other device regions. This localized approach allows short gate lengths while blocking punch-through current at critical points.
Solution Approach 2:
The BEI intrusions act as intermediary doping regions between the channel and the N+ source/drain regions, providing a gradual doping transition that modifies the electric field profile. This intermediary structure prevents direct punch-through by creating a doping gradient that blocks carrier flow while allowing the gate length to be reduced for scaling.
3Reliability
If LDD region doping is increased to enhance breakdown voltage, then breakdown voltage is improved, but device complexity increases
Solution Approach 1:
The doping profile is segmented into distinct regions: the lightly doped LDD regions, the breakdown-enhancement BEI intrusions with intermediate doping, and the heavily doped N+ source/drain regions. This segmentation allows each region to be optimized independently for its specific function while maintaining overall device simplicity through a structured, multi-layer doping approach.
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 BEI intrusions effectively increase the breakdown voltage and reduce punch-through current, enhancing the scalability and performance of high-voltage devices without degrading their breakdown voltage, even at miniaturized gate lengths.
Implementation Method 1
implanting a chemical species within lightly doped drain (LDD) regions extending into a semiconductor substrate to form breakdown-enhancement implant (BEI) regions within the LDD regions
Data Source
AI summary
An apparatus includes lightly doped drain regions vertically extending into a semiconductor substrate. A channel region is horizontally interposed between the lightly doped drain regions, and source/drain regions vertically extend into the lightly doped drain regions. Breakdown-enhancement implant intrusion regions are within the lightly doped drain regions and are horizontally interposed between the channel region and the source/drain regions. The breakdown enhancement implant regions have a different chemical species than the lightly doped drain regions and have upper boundaries vertically underlying upper boundaries of the lightly doped drain regions. The apparatus also has a gate structure vertically overlying the channel regions and it is horizontally interposed between the breakdown-enhancement implant regions. Memory devices, electronic systems, and methods of forming microelectronic devices are also described.