Super Junction Semiconductor Field Extension Zones
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Solution Overview
Problem
Current super junction semiconductor devices face challenges in improving avalanche characteristics without adversely affecting on-state characteristics, particularly in achieving high reverse breakdown voltage at high impurity concentrations in n-doped columns.
Innovation Solution
The introduction of a super junction semiconductor device with a varying compensation rate between p-doped and n-doped columns, featuring a body zone and field extension zones of opposite conductivity types, which are electrically connected, allowing for controlled impurity density and distribution to enhance avalanche performance while maintaining robust on-state characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high impurity concentration is used in n-doped columns to improve on-state characteristics, then on-state characteristics are improved, but reverse breakdown voltage decreases
Solution Approach 1:
The drift layer is segmented into alternating p-doped and n-doped columns, creating a super junction structure. This segmentation allows the n-doped columns to provide high carrier concentration for good on-state characteristics while the p-doped columns enable depletion region extension for high reverse breakdown voltage, resolving the contradiction between on-state performance and breakdown voltage.
Solution Approach 2:
Different regions of the semiconductor device are given different doping characteristics: the n-doped columns have high impurity concentration for low on-resistance, while the p-doped columns have controlled impurity concentration to enable wide depletion region formation. This local differentiation allows simultaneous optimization of on-state characteristics and reverse breakdown voltage.
2Strength
If depletion zones extend laterally between p-doped and n-doped columns to achieve high reverse breakdown voltage, then reverse breakdown voltage is improved, but device complexity increases
Solution Approach 1:
The drift layer is divided into alternating p-doped and n-doped columns with periodic arrangement. This segmentation creates natural interfaces for depletion zone formation while maintaining a relatively simple fabrication process through sequential doping steps, balancing breakdown voltage improvement with manufacturing complexity.
3Reliability
If vertical impurity distribution is varied to improve avalanche characteristics, then avalanche characteristics are improved, but manufacturing precision requirements increase
Solution Approach 1:
The impurity distribution is arranged in a periodic pattern with alternating p-doped and n-doped columns. This periodic structure allows controlled variation of vertical impurity distribution to optimize avalanche characteristics while maintaining manufacturability through repetitive doping processes, reducing the complexity of precision control compared to aperiodic variations.
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 design achieves a high breakdown voltage and improved avalanche characteristics by managing the electric field distribution, ensuring device stability and efficiency across various operational modes.
Implementation Method 1
managing the electric field distribution, ensuring device stability and efficiency
Implementation Method 2
improved the avalanche characteristics of super junction semiconductor devices
Data Source
AI summary
A super junction semiconductor device includes an impurity layer of a first (conductivity) type formed in a semiconductor portion having first and second parallel surfaces, a super junction structure between the first surface and impurity layer and including first columns of the first type and second columns of a second (conductivity) type, a body zone of the second type formed between the first surface and one of the second columns at least partially in the vertical projection of the second columns, and a field extension zone of the second type electrically connected to the body zone and arranged in the vertical projection of one of the columns. An area impurity density in the field extension zone is between 1×1012 and 5×1012 cm−2. A mean net impurity concentration in the field extension zone is higher than in the second columns and lower than in the body zone.