Semiconductor Device p-Type Low-Dose Region Parasitic Diode
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Solution Overview
Problem
Conventional semiconductor devices face challenges with high current density and switching frequency limitations, particularly due to the large surface area of the main non-operating region which increases the operating region of parasitic diodes, leading to susceptibility to destruction during switching operations.
Innovation Solution
A semiconductor device design utilizing a p-type low-dose region with a lower impurity concentration surrounding the sensing effective region, which reduces the surface area of the main non-operating region and increases the resistance, thereby mitigating the flow of positive holes and enhancing the reverse recovery resistance of parasitic diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the surface area of the main non-operating region is large, then the device can accommodate more circuit portions for protecting/controlling the main semiconductor element, but the operating region of parasitic diodes increases leading to susceptibility to destruction during switching operations
Solution Approach 1:
The patent applies local quality by creating a p-type low-dose region with specifically lower impurity concentration in the main non-operating region. This localized modification reduces the operating region of parasitic diodes in critical areas while maintaining the overall structure capable of accommodating circuit portions. The differentiated impurity concentration creates zones with different electrical characteristics to suppress harmful currents locally without compromising the device's functional capacity.
2Ease of manufacture
If a conventional p-type base region structure is used, then the manufacturing process is simple, but the parasitic diode operating region is large causing device destruction during switching
Solution Approach 1:
The patent introduces a p-type low-dose region with lower impurity concentration in the main non-operating region, creating a localized structural differentiation. This can be integrated into conventional manufacturing processes by adding selective ion implantation or diffusion steps for the low-dose region, maintaining manufacturing simplicity while significantly improving switching operation safety by reducing parasitic diode operating regions.
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 design effectively suppresses positive hole current flow, increases the reverse recovery resistance of parasitic diodes, and enhances the breakdown voltage, improving the reliability and efficiency of the semiconductor device.
Implementation Method 1
reduces the surface area of the main non-operating region and increases the resistance, thereby mitigating the flow of positive holes
Implementation Method 2
MOSFETs structurally differ from IGBTs, have a built-in parasitic diode formed by a pn junction between a p-type base region and an n−-type drift region
Data Source
AI summary
A region of a portion directly beneath an OC pad is a sensing effective region in which unit cells of a current sensing portion are disposed. A p-type low-dose region is provided on a front surface of a semiconductor substrate and surrounds a periphery of the sensing effective region. The p-type low-dose region is fixed at an electric potential of a source pad of a main semiconductor element. The p-type low-dose region is disposed to be separated from a p-type base region of the sensing effective region by an n−-type region between the p-type low-dose region and the sensing effective region. A total dose of impurities in the p-type low-dose region is lower than a total dose of impurities in a p-type region of a front side of a semiconductor substrate in a main effective region in which unit cells of the main semiconductor element are disposed.