MOSFET Array Guard Ring Layout for Higher Withstand Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits with MOSFET arrays face insufficient withstand voltage, particularly in high-voltage applications, leading to defects and reduced performance, and increasing MOSFET count to address this issue increases manufacturing costs.
Innovation Solution
A guard ring with multiple ring regions is placed around the transistor array, featuring varying doped areas to divert surge currents outward, enhancing the circuit's withstand voltage to 1500 volts or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of MOSFETs in the array is increased to achieve required withstand voltage, then the withstand voltage capability is improved, but the manufacturing cost significantly increases
Solution Approach 1:
A guard ring structure is introduced as an intermediary element between the MOSFET array and the substrate. This guard ring includes a first doped region extending from a first edge of the array and a second doped region extending from a second edge, with the second doped region having a greater depth than the first. This asymmetric doped structure acts as a mediator to enhance withstand voltage by controlling electric field distribution and preventing substrate breakdown, thereby achieving high voltage capability without increasing MOSFET count or manufacturing cost.
2Reliability
If the number of MOSFETs is increased to achieve required withstand voltage, then the circuit reliability is improved, but the device complexity increases
Solution Approach 1:
The guard ring structure serves as an intermediary that enhances withstand voltage capability without requiring additional MOSFETs. By implementing asymmetric doped regions in the guard ring (with the second doped region having greater depth than the first), the patent controls electric field distribution to prevent substrate breakdown. This approach improves reliability while maintaining the existing MOSFET array configuration, thus avoiding increased device complexity.
3Reliability
If conventional guard ring structures are used, then some protection is provided, but the withstand voltage is insufficient for high-voltage applications
Solution Approach 1:
The patent applies local quality by creating asymmetric doped regions within the guard ring structure. Specifically, the second doped region extending from the second edge has a greater depth than the first doped region extending from the first edge. This localized variation in doped region depth optimizes electric field distribution at different edges of the MOSFET array, providing enhanced protection against substrate breakdown in high-voltage applications while maintaining overall structural integrity.
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 guard ring design improves the transistor array's withstand voltage by 20% to 50%, effectively dispersing surge currents and heat, thus protecting the circuit and reducing manufacturing costs.
Implementation Method 1
When a surge occurs during circuit operation, the surge current can be diverted outward through the ring regions
Implementation Method 2
The doped area of an inner side of the ring regions is greater than the doped area of an outer side of the ring regions, withstand voltage of the transistor array in the circuit can be significantly increased to 1500 volts or more
Data Source
AI summary
An integrated circuit is provided. The integrated circuit includes a transistor array and a guard ring. The guard ring is formed on a periphery of the transistor array. The guard ring includes a plurality of ring regions, and each of the ring regions includes a doped area. A doped area of an inner side of the ring regions is greater than a doped area of an outer side of the ring regions.