Field Stop Semiconductor Component for Blocking Voltage
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Solution Overview
Problem
High-voltage semiconductor switches face challenges in achieving both high blocking voltage and low on-state resistance due to conflicting requirements, leading to reverse current chopping and oscillations that can impair electromagnetic compatibility and potentially destroy the switch.
Innovation Solution
A field effect controllable semiconductor component with a field stop zone of heavier doping than the drift zone but lighter than the terminal zones, which acts as a field stop to optimize field distribution and reduce reverse current chopping, combined with a recombination zone to promote charge carrier recombination and a charge compensation structure to balance charge carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a more weakly doped drift zone is provided to increase blocking voltage, then blocking ability is improved, but on-state resistance increases
Solution Approach 1:
The patent introduces a field stop zone with intermediate doping concentration between the heavily doped terminal zone and the weakly doped drift zone. This creates a non-uniform doping profile where different regions have optimized doping levels for their specific functions: the field stop zone provides field control to prevent premature breakdown while maintaining lower on-state resistance in the drift zone.
Solution Approach 2:
The patent changes the doping concentration parameter along the vertical direction, creating a graded doping profile. The field stop zone has a doping concentration that is higher than the drift zone but lower than the terminal zone, which modifies the electric field distribution to simultaneously achieve high blocking voltage and low on-state resistance.
2Adaptability or versatility
If the inverse diode is allowed to conduct reverse current, then freewheeling function is improved, but reverse current chopping causes oscillations and EMC problems
Solution Approach 1:
The field stop zone is positioned to preemptively control the electric field distribution before reverse current chopping occurs. By establishing a controlled field gradient in the field stop zone, the patent prevents the formation of high di/dt conditions that lead to oscillations and EMC problems, while still allowing the inverse diode to perform its freewheeling function.
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 field stop zone effectively reduces reverse current losses and prevents premature avalanche breakdown, while the recombination zone decreases charge storage, thereby minimizing oscillations and enhancing the switch's stability and efficiency.
Implementation Method 1
prevents premature avalanche breakdown
Implementation Method 2
a recombination zone to promote charge carrier recombination and decrease charge storage
Implementation Method 3
a charge compensation structure to balance charge carriers
Data Source
AI summary
The invention relates to a semiconductor component, which comprises a semiconductor body having a first and a second terminal zone of a first conduction type (n), a channel zone of a second conduction type (p), which is short circuited with the second terminal zone, a drift zone of the first conduction type (n) with weaker doping than the terminal zones, which drift zone is formed between the channel zone and the first terminal zone, the channel zone being formed between the drift zone and the second terminal zone, a control electrode, formed so that it is insulated from the channel zone, for controlling a conductive channel in the channel zone between the second terminal zone and the drift zone, and is distinguished in that a field stop zone of the first conduction type (n) is formed between the first terminal zone and the drift zone, the field stop zone having heavier doping than the drift zone and weaker doping than the first terminal zone, the maximum doping of the field stop zone being at most a factor of about 102 heavier than the doping of the drift zone.