Alternating Semiconductor Zones for Charge Compensation
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Solution Overview
Problem
Production tolerances and lithographic mismatches in semiconductor devices lead to deviations in charge compensation of n- and p-doped regions, affecting device performance such as breakdown voltage and maximum doping concentration.
Innovation Solution
The semiconductor device incorporates compensation zones with alternately arranged first and second semiconductor zones of different conductivity types, where the diffusion coefficient of the second dopant species is at least twice that of the first, allowing precise charge compensation and improved breakdown voltage through careful dopant implantation and diffusion profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If production tolerances and lithographic mismatches occur in conventional semiconductor devices, then manufacturing cost and ease of manufacture are maintained, but charge compensation of n- and p-doped regions deviates from desired values, leading to decreased breakdown voltage and limited maximum doping concentration
Solution Approach 1:
The device is segmented into multiple alternating semiconductor zones (first zones with first conductivity type, second zones with second conductivity type) arranged along a lateral direction. This segmentation allows the charge compensation function to be distributed across multiple zones rather than relying on a single doped region, thereby reducing the impact of lithographic mismatches and production tolerances on overall charge compensation precision while maintaining high breakdown voltage
Solution Approach 2:
Different semiconductor zones are assigned different conductivity types (n-type or p-type) and different dopant concentrations locally along the lateral direction. Each zone is optimized with specific dopant species and concentrations to achieve local charge compensation, allowing the device to tolerate variations in individual zones while maintaining overall performance and high breakdown voltage
2Reliability
If dopant concentration in drift zones is increased to reduce on-resistance, then on-resistance improves, but charge compensation becomes more sensitive to production tolerances and lithographic mismatches
Solution Approach 1:
The drift zone is segmented into multiple alternating n-type and p-type semiconductor zones along the lateral direction. By distributing the high dopant concentration across multiple segmented zones rather than a single continuous region, the device achieves low on-resistance while the alternating polarity zones provide distributed charge compensation that is less sensitive to lithographic mismatches and production tolerances
Solution Approach 2:
The invention changes the spatial distribution parameter of dopant concentration by creating alternating zones with different conductivity types and concentrations along the lateral direction. This parameter change allows maintaining high average dopant concentration for low on-resistance while the alternating pattern provides inherent tolerance to manufacturing variations through distributed charge compensation
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 charge compensation, reduces on-resistance, and improves avalanche robustness while maintaining low production costs and tolerating lithographic misalignments, resulting in improved semiconductor device performance.
Implementation Method 1
a diffusion coefficient of the second dopant species is at least twice that of the first dopant species
Data Source
AI summary
A semiconductor device includes first semiconductor zones of a first conductivity type having a first dopant species of the first conductivity type and a second dopant species of a second conductivity type different from the first conductivity type. The semiconductor device also includes second semiconductor zones of the second conductivity type including the second dopant species. The first and second semiconductor zones are alternately arranged in contact with each other along a lateral direction extending in parallel to a surface of a semiconductor body. One of the first and second semiconductor zones constitute drift zones and a diffusion coefficient of the second dopant species is at least twice as large as the diffusion coefficient of the first dopant species. A concentration profile of the first dopant species along a vertical direction perpendicular to the surface of the semiconductor body includes at least two maxima.