Semiconductor Component Trench Doping for Breakdown Voltage
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Solution Overview
Problem
Power semiconductor components face challenges in managing high electric field strengths during the off-state, leading to potential electrical breakdowns and reduced reliability, especially when switching high load currents, due to limitations in breakdown voltage and threshold voltage control.
Innovation Solution
A method for producing field effect controllable semiconductor components involves forming buried n-conducting layers and p-doped protective regions around trench bottoms, which reduces high electric field strengths and enhances breakdown voltage by shifting the electric field distribution deeper into the semiconductor body, thereby improving dynamic switching and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power semiconductor components are used, then they can operate in standard conditions, but they suffer from electrical breakdowns and reduced reliability when exposed to high electric field strengths during switching of high load currents
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping structure with a gradient in the drift region. The doping concentration varies spatially, being higher near the trench structures and lower in other regions. This localized variation in doping quality allows the component to withstand high electric field strengths at critical locations while maintaining overall device performance and reliability.
Solution Approach 2:
The patent introduces a vertical dimension to the doping structure by forming trench structures that extend into the drift region. This three-dimensional doping architecture, with buried layers and trench-based doping, redistributes the electric field in the vertical dimension, preventing concentration of high electric field strengths at the surface and improving breakdown voltage.
2Reliability
If breakdown voltage is increased to prevent electrical breakdowns, then reliability improves, but threshold voltage control becomes more difficult and dynamic switching capabilities are reduced
Solution Approach 1:
The patent utilizes parameter changes by varying the doping concentration across different regions of the drift region. By controlling the doping gradient and creating specific doping profiles in the buried layers and trench regions, the patent simultaneously achieves high breakdown voltage and proper threshold voltage control. The doping parameters are optimized to balance these two requirements.
Solution Approach 2:
The patent enables dynamic adaptability by creating a doping structure that allows the component to dynamically respond to voltage spikes during switching. The gradient doping structure provides dynamic threshold voltage control, allowing the device to adapt its electrical characteristics during transient conditions while maintaining high breakdown voltage for reliability.
3Adaptability or versatility
If active clamping elements and overvoltage protective elements are added to manage voltage spikes, then dynamic adaptability improves, but total resistance increases
Solution Approach 1:
The patent extracts the need for external protective elements by integrating overvoltage protection functionality directly into the semiconductor structure itself. The gradient doping drift region and trench structures provide inherent protection against voltage spikes, eliminating or reducing the need for separate active clamping elements and overvoltage protective elements, thereby avoiding additional resistance.
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 method effectively reduces the risk of electrical breakdowns, enhances dynamic switching capabilities, and improves the reliability of power semiconductor components by optimizing breakdown voltage and threshold voltage, allowing for better adaptability to voltage spikes without increasing total resistance.
Implementation Method 1
reduces high electric field strengths and enhances breakdown voltage by shifting the electric field distribution deeper into the semiconductor body
Implementation Method 2
forming buried n-conducting layers and p-doped protective regions
Data Source
AI summary
A method for producing a semiconductor component is proposed. The method includes providing a semiconductor body having a first surface; forming a mask on the first surface, wherein the mask has openings for defining respective positions of trenches; producing the trenches in the semiconductor body using the mask, wherein mesa structures remain between adjacent trenches; introducing a first dopant of a first conduction type using the mask into the bottoms of the trenches; carrying out a first thermal step; introducing a second dopant of a second conduction type, which is complementary to the first conduction type, at least into the bottoms of the trenches; and carrying out a second thermal step.