Semiconductor Device Anode Segmentation for Recovery and Breakdown
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Solution Overview
Problem
Semiconductor devices face challenges in improving recovery characteristics while preventing breakdown due to depletion layer extension and ohmic contact issues under forward and reverse biases.
Innovation Solution
The semiconductor device incorporates a structure with multiple semiconductor regions of varying impurity concentrations and an insulating film, where the anode electrode is connected to a high impurity concentration region via a low impurity concentration region, and an additional n-type semiconductor region is introduced to reduce positive hole accumulation and extend the current path, enhancing recovery characteristics and static withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the concentration of the anode region is reduced to improve recovery characteristics, then the amount of positive hole accumulation decreases, but the depletion layer extends easily toward the anode electrode causing breakdown
Solution Approach 1:
The anode region is segmented into two distinct parts: a first anode region with lower impurity concentration and a second anode region with higher impurity concentration. This segmentation allows each region to perform its specialized function - the first region reduces hole accumulation for improved recovery characteristics, while the second region prevents depletion layer extension to maintain breakdown resistance.
Solution Approach 2:
Different regions of the anode are given different impurity concentrations tailored to their specific functions. The first anode region has lower concentration optimized for reducing hole accumulation, while the second anode region has higher concentration optimized for preventing depletion layer extension. This local quality differentiation resolves the contradiction by optimizing each location for its specific role.
2Loss of energy
If the concentration of the anode region is reduced to reduce positive hole supply, then recovery characteristics improve, but the depletion layer reaches the anode electrode more easily
Solution Approach 1:
The anode region is divided into two segments with different impurity concentrations. The first anode region with lower concentration reduces positive hole supply to decrease switching loss, while the second anode region with higher concentration acts as a barrier to prevent depletion layer extension, thereby maintaining high breakdown voltage.
Solution Approach 2:
The anode structure implements local quality variation where the first anode region has lower impurity concentration optimized for reducing switching loss, and the second anode region has higher impurity concentration optimized for maintaining breakdown voltage. This spatial differentiation of properties resolves the contradiction between reducing energy loss and maintaining reliability.
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 configuration improves recovery characteristics by reducing positive hole accumulation and suppressing depletion layer extension, leading to better switching loss and static withstand voltage performance.
Implementation Method 1
the amount of positive hole supplied from the anode region 14 at the time of forward bias decreases
Implementation Method 2
a depletion layer extends easily from the intermediate semiconductor region 1 toward the anode region 14 at the time of application of a reverse bias
Data Source
AI summary
Provided is a technique capable of improving performance of a semiconductor device. A semiconductor device includes a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type located on the first semiconductor region, third and fourth semiconductor regions of the second conductivity type, a fifth semiconductor region of the first conductivity type, and an electrode. The third semiconductor region is located on the second semiconductor region, and has a higher impurity concentration than the second semiconductor region. The fourth semiconductor region has a higher impurity concentration than the second semiconductor region, is located separately from the third semiconductor region in a planar view, and has contact with the second semiconductor region. The fifth semiconductor region is located on the second semiconductor region, and is located between the third and fourth semiconductor regions in a planar view. The electrode does not have contact with the fourth and fifth semiconductor regions but has contact with the third semiconductor region.