Semiconductor Layer Structure for High-Voltage Breakdown Immunity
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Solution Overview
Problem
Semiconductor devices used in power converters face challenges in achieving high breakdown immunity at high voltages and currents, leading to reliability issues due to electric field concentration and avalanche breakdown.
Innovation Solution
The semiconductor device incorporates a specific structure with a control electrode insulated from the semiconductor part and second electrode, featuring a unique arrangement of semiconductor layers and electrodes, including a fifth semiconductor layer with a floating potential, which extends between the first and second electrodes, and a termination region with guard rings, to manage electric fields and prevent breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor structure is used, then manufacturing is simpler, but breakdown immunity at high voltages and currents is insufficient
Solution Approach 1:
The semiconductor device is divided into multiple functional layers including first through fifth semiconductor layers with different conductivity types, each serving specific purposes in managing electric fields and current flow. The termination region is segmented with guard rings and the control electrode is separated by insulating films, creating distinct functional zones that collectively improve breakdown immunity without requiring complete redesign of the entire device.
Solution Approach 2:
Different regions of the semiconductor device are assigned different properties: the termination region contains guard rings and specific layer configurations for voltage handling, while the active region optimizes for current conduction. The fifth semiconductor layer is positioned at specific locations with particular conductivity types to locally manage electric field distribution where breakdown risks are highest.
2Reliability
If electric field concentration is not managed, then device structure is simpler, but avalanche breakdown occurs at high voltages
Solution Approach 1:
Guard rings and the fifth semiconductor layer act as intermediary elements between high-voltage regions and lower-voltage regions. These intermediate structures gradually transition the electric field intensity, preventing sudden concentration and avalanche breakdown. The insulating films between the control electrode and semiconductor layers also serve as intermediaries to distribute and manage electric fields in the control region.
3Reliability
If control electrode is not insulated, then manufacturing is easier, but snapback phenomenon occurs reducing breakover immunity
Solution Approach 1:
First and second insulating films are introduced as intermediary layers between the control electrode and the semiconductor layers. These insulating films prevent direct electrical contact that would cause snapback, while being deposited using standard semiconductor manufacturing techniques such as CVD or PECVD, maintaining reasonable manufacturing ease.
4Reliability
If termination region is not optimized, then device structure is simpler, but charge robustness is reduced under high current conditions
Solution Approach 1:
The termination region is segmented into multiple functional zones including guard rings, specific semiconductor layer configurations, and insulating regions. This segmentation allows each zone to handle specific aspects of voltage and current management, improving charge robustness through distributed functionality rather than a single monolithic structure.
Data Source
AI summary
A semiconductor device includes a semiconductor part, first and second electrodes and a control electrode. The semiconductor part is provided between the first and second electrode. The semiconductor part includes first and third layers of a first conductivity type, and second, fourth and fifth layers of a second conductivity type. The first layer extends between the first and second electrodes. The second layer is provided between the first layer and the second electrode. The third semiconductor layer is provided between the second layer and the second electrode. The fourth layer is provided between the first layer and the first electrode. The semiconductor part includes an active region and a termination region. The active region includes the control electrode, the second layer, and the third layer. The termination region surrounds the active region. The fifth layer is provided in the first layer in the termination region.