Trench-Gated Thyristor and Rectifier Integration on Single Die
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Solution Overview
Problem
Thyristor circuits face challenges with latching issues, where once turned on, they remain on as long as voltage allows current flow, and integrating a freewheeling diode with thyristors in motor drive applications is complex due to separate semiconductor dies and thermal conductivity requirements.
Innovation Solution
Combining a MOS-controlled thyristor with a trench gate rectifier on a single semiconductor die, eliminating the need for separate internal leads and sharing thermal conductivity, with both devices connected to the same current-carrying terminals, allowing for efficient high-voltage switching with reduced parasitic inductance and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a thyristor and freewheeling diode are integrated on a single semiconductor die, then device complexity and packaging requirements are reduced, but thermal conductivity management becomes more challenging due to different thermal requirements for each device
Solution Approach 1:
The patent combines a thyristor and freewheeling diode on a single semiconductor die, integrating two separate devices into one unified structure. This merging reduces device complexity and eliminates the need for separate packaging, while the shared thermal path accommodates the thermal requirements of both devices through careful structural design
Solution Approach 2:
The semiconductor die is designed to serve multiple functions simultaneously - housing both the thyristor for high-voltage switching and the freewheeling diode for current recirculation. The shared thermal conductivity structure provides universal thermal management for both devices, eliminating the need for separate thermal paths
2Temperature
If separate semiconductor dies are used for thyristor and diode, then thermal conductivity requirements can be optimized for each device, but device complexity and packaging requirements increase
Solution Approach 1:
Rather than using separate dies, the patent merges the thyristor and diode onto a single semiconductor die. This integration simplifies the overall device structure and packaging requirements while the shared thermal conductivity path is designed to accommodate both devices' thermal needs through unified thermal management
3Reliability
If internal leads are used to connect thyristor and diode, then electrical connections can be established, but parasitic inductance and capacitance increase
Solution Approach 1:
The patent integrates the thyristor and diode so closely on the same die that they share common current-carrying terminals. This merging eliminates the need for separate internal leads and connections, thereby removing the parasitic inductance and capacitance that would be introduced by traditional wired connections
Solution Approach 2:
The invention extracts and eliminates the internal lead connections from the device structure. By directly integrating the devices to share terminals, the harmful internal leads are removed entirely, reducing parasitic reactance while maintaining reliable electrical connections
Data Source
AI summary
An integrated trench-MOS-controlled-thyristor plus trench gated diode combination, in which the trenches are preferably formed at the same time. A backside polarity reversal process permits a backside p+ region in the thyristor areas, and only a backside n+ region in the diode areas (for an n-type device). This is particularly advantageous in motor control circuits and the like, where the antiparallel diode permits the thyristor to be dropped into existing power MOSFET circuit designs. In power conversion circuits, the antiparallel diode can conveniently serve as a freewheeling diode.