LDMOS Transistor with Integrated Breakdown Diode
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Solution Overview
Problem
High-voltage LDMOS transistors face intrinsic breakdown events that can lead to device degradation and failure, particularly due to high operational voltages, and existing solutions like parallel clamping devices increase fabrication costs and are not scalable.
Innovation Solution
Integration of internal lateral and vertical junction breakdown protection diodes within the transistor device, spaced from the channel region, to redirect breakdown events away from the normal conduction path, allowing for scalable protection without increasing device size or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second device is used in parallel to clamp the drain voltage and prevent intrinsic breakdown, then the device reliability is improved, but the fabrication cost increases
Solution Approach 1:
The patent merges the protection function into the existing LDMOS device structure by forming a pn junction between the p-type body region and n-type drift region. This integrated approach eliminates the need for a separate parallel clamping device, thereby maintaining reliability while reducing fabrication cost and complexity.
Solution Approach 2:
The LDMOS device protects itself from intrinsic breakdown through the integrated pn junction that automatically activates during breakdown events. The device structure provides its own protection mechanism without requiring external components,实现ing self-service protection.
2Reliability
If a lateral clamp diode is used in the end termination regions, then the breakdown protection is improved, but the device scalability is worsened due to photo misalignments affecting breakdown voltage
Solution Approach 1:
The protection function is merged into the active area of the LDMOS device rather than being placed in end termination regions. This integration allows the protection mechanism to scale with the transistor width without being affected by photo misalignment issues, improving both reliability and scalability.
3Reliability
If the active area is fully isolated by extending the device separating region across the active area, then the breakdown protection is improved, but the device complexity and size increase
Solution Approach 1:
The device separating region is strategically positioned to provide breakdown protection at critical locations (forming the pn junction between body and drift regions) without extending across the entire active area. This localized approach maintains necessary protection while minimizing device complexity and size.
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
The integrated breakdown protection diodes effectively redirect and manage breakdown events, preventing device damage while maintaining the transistor's operational integrity and scalability, without adding fabrication costs or complexity.
Implementation Method 1
the pn junction is configured such that a breakdown event is spaced from a channel or other conduction region of the power transistor device... the pn junction is configured such that a breakdown event is spaced from a channel or other conduction region of the power transistor device
Data Source
AI summary
A semiconductor device configured with one or more integrated breakdown protection diodes in non-isolated power transistor devices and electronic apparatus, and methods for fabricating the devices.