Guard Ring Structure for Suppressing Electric Field Concentration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor devices face challenges in suppressing electric field concentration on the surface of insulating protection films, which can lead to creeping discharge, and are also susceptible to electric field disturbances from trapped charges in the insulating protection film.
Innovation Solution
The semiconductor device incorporates guard ring regions with a low concentration region in direct contact with the insulating protection film and a high concentration region separated from it, allowing for dispersion of equipotential lines and reducing electric field concentration, while the low concentration regions are depleted to minimize the impact of trapped electric charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the high concentration region of the guard ring region is in direct contact with the insulating protection film, then the guard ring region can effectively control electric field distribution, but electric field concentration occurs on the surface of the insulating protection film causing creeping discharge
Solution Approach 1:
The guard ring region is segmented into two distinct concentration zones: a high concentration region for effective electric field control and a low concentration region for preventing surface electric field concentration. This segmentation allows each region to perform its specific function without causing harmful effects.
Solution Approach 2:
Different regions of the guard ring structure are assigned different impurity concentrations tailored to their specific functions. The high concentration region (1×10^19 to 1×10^20 atoms/cm³) is positioned away from the insulating film for field control, while the low concentration region (1×10^16 to 1×10^18 atoms/cm³) contacts the insulating film to prevent surface concentration.
2Object-affected harmful factors
If the guard ring region is spaced apart from the insulating protection film, then electric field concentration on the insulating protection film surface is suppressed, but electric field in the drift region is disturbed by electric charges trapped in the insulating protection film
Solution Approach 1:
The low concentration region acts as an intermediary between the high concentration region and the insulating protection film. It provides a transition zone that maintains electrical connection while preventing direct contact between high concentration charges and the insulating film surface, thereby avoiding both electric field concentration and charge trapping effects.
Solution Approach 2:
The low concentration region serves as a protective intermediary layer that shields the drift region from electric charges trapped in the insulating protection film, while still allowing the high concentration region to effectively control the electric field distribution through the low concentration region.
3Device complexity
If a single concentration guard ring region is used, then the structure is simple, but either electric field concentration occurs or electric field disturbance from trapped charges occurs
Solution Approach 1:
The guard ring region is divided into two functional segments with different impurity concentrations, allowing simultaneous achievement of electric field control and prevention of electric field concentration, thereby maintaining high reliability without excessive complexity.
Solution Approach 2:
Each region within the guard ring structure is assigned specific local properties (high or low impurity concentration) optimized for its function, enabling the overall structure to achieve superior electrical performance while maintaining a relatively simple integrated design.
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 effectively reduces electric field concentration on the surface of the insulating protection film, preventing creeping discharge and minimizing disturbances to the drift region from trapped charges, thereby enhancing the semiconductor device's withstand voltage.
Implementation Method 1
electric field can be easily concentrated on a surface of the insulating protection film
Implementation Method 2
The guard ring low concentration regions with a low p-type impurity concentration can be easily depleted
Data Source
AI summary
A semiconductor device includes a semiconductor substrate that includes an element region and a peripheral withstand voltage region. An insulating protection film is provided above the peripheral withstand voltage region. The peripheral withstand voltage region includes a plurality of guard ring regions of p-type in direct contact with the insulating protection film and a drift region of n-type separating the guard ring regions from each other. Each guard ring region includes a guard ring low concentration region being in direct contact with the insulating protection film and a guard ring high concentration region having a p-type impurity concentration equal to or more than ten times as high as that in the corresponding guard ring low concentration region. Each guard ring high concentration region is provided under the corresponding guard ring low concentration region, and separated from the insulating protection film by the corresponding guard ring low concentration region.