Gate Dielectric Breakdown Reduction via Segmented Dopant Profiles
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Solution Overview
Problem
The operational lifetime of transistors is compromised due to dielectric breakdown, with hard breakdown leading to complete device failure, and existing technologies struggle to maintain reliability as gate oxide thickness decreases, necessitating a solution to extend the operational life by reducing the likelihood of hard breakdown.
Innovation Solution
The implementation of a semiconductor device with a first area of transistors having a lower dopant concentration and a second area with a resistor region within the gate structure, both operating at the same voltage, to increase the ratio of soft to hard breakdown, thereby extending the operational life by reducing the probability of hard breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gate oxide thickness is decreased to improve transistor on-current, then on-current increases, but dielectric breakdown probability increases
Solution Approach 1:
The gate structure is segmented into two distinct areas: a first area with lower dopant concentration and larger area, and a second area with higher dopant concentration and smaller area. This segmentation allows different regions to serve different functions - the first area provides reliability and resistance to dielectric breakdown, while the second area provides high on-current capability.
Solution Approach 2:
Different regions of the gate are assigned different dopant concentrations tailored to their specific functional requirements. The first area has lower dopant concentration optimized for reliability and breakdown resistance, while the second area has higher dopant concentration optimized for current conduction, allowing each local region to have the quality needed for its purpose.
2Speed
If dopant concentration in gate is increased to improve transistor switching speed, then switching speed increases, but hard breakdown probability increases
Solution Approach 1:
The gate is divided into two areas with different dopant concentrations. The second area with higher dopant concentration provides fast switching speed, while the first area with lower dopant concentration provides protection against hard breakdown, thus segmenting the conflicting requirements into separate spatial regions.
Solution Approach 2:
High dopant concentration is applied locally in the second area to achieve fast switching, while low dopant concentration is applied in the first area to prevent hard breakdown. This local differentiation of quality allows simultaneous optimization of speed and reliability in different parts of the same gate structure.
3Productivity
If gate area is reduced to increase transistor density, then transistor density increases, but operational lifetime decreases
Solution Approach 1:
The gate structure uses local quality differentiation where the first area has lower dopant concentration optimized for long operational lifetime and breakdown resistance, while the second area has higher dopant concentration for performance. This allows the overall gate area to be optimized for density while specific local regions maintain properties that extend operational lifetime.
Data Source
AI summary
The present invention, in one aspect, provides an integrated circuit that comprises a first region of transistors having gate structures with a low dopant concentration, and a second region of transistors having gate structures with a dopant concentration substantially higher than the gate structures of the first region, and wherein the transistors in the first region comprise a substantial portion of the integrated circuit. The transistors may include a resistor region located between an upper portion of the gate and the gate dielectric.