Super Junction Semiconductor Deep Layer Charge Dispersion
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Solution Overview
Problem
In semiconductor devices with a super junction (SJ) structure, the concentration of injected charge during recovery operations can lead to damage at the boundary between the p-type body layer and the source electrode, as well as potential damage to the gate insulating film, due to high heat generation at the contact end with the p-type resurf layer.
Innovation Solution
A semiconductor device is designed with a deep layer of higher impurity concentration than the SJ structure, which overlaps with the high impurity layer and the SJ structure, to relax the concentration of injected charge and reduce heat generation, thereby preventing damage to the element and the gate insulating film. This deep layer is formed by ion implantation and epitaxial growth, or through high acceleration ion implantation, ensuring excellent crystalline quality and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the p type resurf layer is made high in concentration to ensure high breakdown voltage, then the breakdown voltage is improved, but the injected charge becomes concentrated and causes damage to the boundary between the p type body layer and source electrode
Solution Approach 1:
The patent applies local quality by creating different impurity concentration zones within the p type resurf layer. Specifically, a first p type impurity region with higher concentration is formed at the surface, while a second p type impurity region with lower concentration is formed at a deeper position. This spatial differentiation allows the surface region to provide high breakdown voltage while the deeper region reduces charge concentration, thereby resolving the contradiction between strength and harmful effects.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a single-layer p type resurf structure to a multi-layer vertical structure. By introducing depth as an additional dimension and forming impurity regions at different depths (surface region and deeper region), the patent achieves both high breakdown voltage at the surface and reduced charge concentration at depth, effectively solving the technical contradiction through dimensional expansion.
2Strength
If the p type resurf layer is made high in concentration, then the breakdown voltage is improved, but heat generation increases and damages the gate insulating film
Solution Approach 1:
The patent applies local quality by creating different impurity concentration zones within the p type resurf layer. Specifically, a first p type impurity region with higher concentration is formed at the surface, while a second p type impurity region with lower concentration is formed at a deeper position. This spatial differentiation allows the surface region to provide high breakdown voltage while the deeper region reduces charge concentration, thereby resolving the contradiction between strength and harmful effects.
Solution Approach 2:
The patent resolves the contradiction by changing the impurity concentration parameter through depth. By forming a high-concentration region at the surface and a low-concentration region at depth, the patent optimizes the breakdown voltage while reducing heat generation. This parameter variation with position allows simultaneous achievement of high voltage capability and reduced thermal effects.
3Stability of the object's composition
If ion implantation is performed to form the deep layer, then the crystalline quality is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies merging by combining multiple impurity formation steps into a single ion implantation process. By simultaneously forming both the first p type impurity region and the second p type impurity region through one ion implantation operation, the patent achieves excellent crystalline quality while avoiding the complexity of multiple separate implantation processes, thereby resolving the contradiction between quality and manufacturing simplicity.
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 deep layer effectively disperses the injected charge, reducing heat generation and preventing damage to the semiconductor device components, while maintaining high recovery capability and breakdown voltage, thus enhancing the reliability and performance of the SJ structure.
Implementation Method 1
This deep layer is formed by ion implantation and epitaxial growth
Implementation Method 2
This deep layer is formed by ion implantation and epitaxial growth
Implementation Method 3
heat generation becomes large in an end of the contact portion of the source electrode J5 with the p type body layer J4
Data Source
AI summary
A semiconductor device has a deep layer with a higher impurity concentration than that of a super junction structure. The deep layer is formed from a position deeper from a surface of a semiconductor layer by a predetermined depth, and comes in contact with a high impurity layer and also comes in contact with the super junction structure. The deep layer overlaps with a portion between a first end which is an outermost peripheral side of a portion that comes in contact with the high impurity layer in a front surface electrode and an end on an outer peripheral side in the high impurity layer when viewed from a substrate normal direction.