Multi-Channel Heterojunction Anode Layout for Higher Breakdown Voltage
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Solution Overview
Problem
Junction Barrier Schottky Diodes with multiple 2DEG channel structures experience premature breakdown due to electric field concentration at the Schottky interface when subjected to large reverse bias voltages.
Innovation Solution
A semiconductor structure with a multi-channel heterojunction layer and anode fingers of varying lengths, where each anode finger partially penetrates the heterojunction layer to control individual channels, thereby avoiding electric field concentration and enhancing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Junction Barrier Schottky Diode with a plurality of 2DEG channel structures is used, then electron mobility rate and conductivity are improved, but electric field concentration occurs at the Schottky interface leading to premature breakdown
Solution Approach 1:
The anode contact is segmented into multiple anode fingers of different lengths, where each anode finger corresponds to and contacts a specific heterojunction layer. This segmentation distributes the electric field across multiple contact points rather than concentrating it at a single interface, thereby preventing electric field peaks while maintaining the multi-channel structure's high electron mobility and conductivity
Solution Approach 2:
Each anode finger is designed with locally optimized properties - different lengths corresponding to different heterojunction depths - allowing each contact region to have tailored electrical characteristics. This local quality optimization ensures that each anode finger-heterojunction interface operates under optimal conditions without creating overall electric field concentration
2Reliability
If multiple 2DEG channel structures are implemented, then series resistance is reduced, but device breakdown occurs prematurely due to electric field peaks
Solution Approach 1:
The anode contact structure is divided into multiple segmented anode fingers, each contacting a specific heterojunction layer. This segmentation distributes the electric field across multiple interfaces, preventing the formation of electric field peaks that would lead to premature breakdown, while preserving the low series resistance benefit of multiple channels
Solution Approach 2:
The patent transitions from a conventional single-plane anode contact to a multi-depth anode finger structure that extends into the vertical dimension. By placing anode fingers at different depths corresponding to different heterojunction layers, the electric field distribution is extended across multiple spatial dimensions, eliminating concentration peaks while maintaining low resistance
Data Source
AI summary
A semiconductor structure includes a substrate and a multi-channel heterojunction layer, and an anode and a cathode. The multi-channel heterojunction layer includes a first layer of heterojunction, . . . , a mth layer of heterojunction, . . . , and a nth layer of heterojunction; and the anode includes at least one set of anode fingers, any one set of anode fingers includes n anode fingers with different lengths, the n anode fingers include a first anode finger, . . . , a mth anode finger, . . . , and a nth anode finger, and the mth anode finger partially penetrates the multi-channel heterojunction layer to the mth layer of heterojunction. A plurality of channels of the semiconductor structure are controlled by a plurality of anode fingers, respectively, avoiding generation of an electric field peak, and further improving a breakdown voltage of the semiconductor structure.