Lateral Series Capacitive Field Shaping for High-Voltage Breakdown
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high voltage semiconductor devices face complications in fabricating and implementing field shaping structures, such as overlapping field plates and individually biased charge control electrodes, which can lead to complex fabrication processes and practical issues like charge leakage.
Innovation Solution
Embedding field shaping regions within the drift region of a semiconductor device, using electrically conductive regions capacitively coupled to each other and isolated from external contacts, to enhance electric field uniformity and increase breakdown voltage, with a lateral geometry that simplifies processing and improves capacitive coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If overlapping field plates are used for field shaping, then breakdown voltage is improved, but fabrication complexity increases
Solution Approach 1:
The field shaping function is segmented into multiple discrete conductive regions (first conductive region, second conductive region, third conductive region) that are capacitively coupled. Each region can be independently formed using standard semiconductor fabrication techniques, avoiding the need for complex overlapping plate structures while achieving the same field shaping effect.
Solution Approach 2:
The conductive regions are strategically positioned at specific locations within the drift region to create localized field shaping effects. The first conductive region is positioned near the high voltage terminal, the second conductive region is positioned at an intermediate location, and the third conductive region is positioned near the low voltage terminal, creating optimized local field distribution throughout the drift region.
2Reliability
If individually biased charge control electrodes are used, then field shaping is improved, but device complexity and biasing implementation difficulty increase
Solution Approach 1:
Multiple charge control functions are merged into a single integrated structure. The first, second, and third conductive regions work together as a unified capacitive network to shape the electric field, eliminating the need for separate biasing circuits and control mechanisms for each electrode.
Solution Approach 2:
The capacitive coupling between conductive regions enables automatic charge distribution and field shaping without external control. The structure self-regulates the electric field distribution based on the applied voltage across the high voltage device, eliminating complex external biasing requirements.
3Reliability
If charge is injected onto floating field conductors, then field shaping is improved, but charge leakage and control precision issues arise
Solution Approach 1:
The conductive regions are designed to achieve equipotential distribution through capacitive coupling, creating a stable electric field configuration. This approach maintains precise field control without requiring precise charge injection, as the potential distribution is determined by the geometric arrangement and capacitive relationships of the conductive 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
This approach increases breakdown voltage by achieving enhanced electric field uniformity in current-carrying parts of the drift region, simplifying fabrication and reducing RC time delays, while being compatible with various semiconductor device structures.
Implementation Method 1
two or more electrically conductive regions that are electrically insulated from each other, and which are capacitively coupled to each other to form a voltage divider dividing a potential between the first and second terminals
Implementation Method 2
an insulating region within which is disposed a plurality of conductive regions that are insulated from each other and from the semiconductor substrate by an insulator
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a source region extending along a top surface of the semiconductor substrate, a drain region extending along the top surface of the semiconductor substrate, and a field shaping region disposed within the semiconductor substrate between the source region and the drain region. A cross-section of the semiconductor substrate extending from the source region to the drain region through the field shaping region includes an insulating region. The semiconductor device also includes an active region disposed within the semiconductor substrate between the source region and the drain region. The active region is disposed adjacent to the field shaping region in a direction perpendicular to the cross-section of the semiconductor substrate extending from the source region to the drain region through the field shaping region.