Split-Gate Vertical Trench MOSFET for Thermal SOA Stability
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Solution Overview
Problem
As technology nodes become smaller, MOSFET devices experience decreased safe-operating-areas (SOA) and operate in a thermally unstable region.
Innovation Solution
A split-gate MOSFET device with gates divided into two groups, each connected to separate gate buses, allowing independent control of the groups to improve SOA and operate in a thermally stable region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If technology nodes become smaller, then device density increases, but safe-operating-area decreases and thermal stability worsens
Solution Approach 1:
The gate is divided into multiple independent gate segments (first gate, second gate, third gate, etc.) that can be controlled separately through isolated gate buses. This segmentation allows different regions of the device to be independently managed, enabling selective activation of channels to maintain adequate safe-operating-area even as overall device density increases.
Solution Approach 2:
The gate bus system is made dynamically controllable, where each gate bus can be independently enabled or disabled. This dynamic control allows the device to adjust its operational characteristics in real-time, optimizing the balance between device density and safe-operating-area by activating only the necessary gate segments under different operating conditions.
2Productivity
If technology nodes become smaller, then device density increases, but thermal stability deteriorates
Solution Approach 1:
The device is segmented into multiple independently controllable gate regions, allowing thermal management by selectively activating or deactivating specific gate segments. This prevents uniform heating across the entire device and enables localized thermal control, maintaining thermal stability despite increased device density.
Solution Approach 2:
The independent gate control enables periodic or alternating activation of different gate segments, which can help distribute thermal load over time and prevent sustained overheating in any single region, thereby improving overall thermal stability in high-density configurations.
3Reliability
If gates are divided into multiple groups with separate gate buses, then safe-operating-area increases, but device complexity increases
Solution Approach 1:
Multiple gate segments are merged into a unified device structure with a common source and drain region, allowing them to function as a single integrated device while maintaining independent control capabilities. This merging approach achieves improved safe-operating-area without proportionally increasing device complexity, as the shared components reduce the overall complexity burden.
Solution Approach 2:
The multiple gate buses are designed with universal control capabilities, where each gate bus can independently control its associated gate segment while potentially being controlled by the same control logic or driver circuitry. This multi-functionality allows the system to achieve enhanced safe-operating-area through independent gate control without requiring completely separate control systems for each gate, thereby limiting the increase in device complexity.
Data Source
AI summary
A semiconductor device includes first, second and third trenches formed in a semiconductor layer having a first conductivity type. Each trench includes a corresponding field plate and a corresponding gate over each field plate. A first body region having a second opposite conductivity type is between the first and second gates, and a second body region having the second conductivity type is located between the second and third gates. A first source region is located over the first body region and a second source region is located over the second body region, the first and second source regions having the first conductivity type. A first gate bus is conductively connected to the first gate and a second gate bus is conductively connected to the second gate, the first gate bus conductively isolated from the second gate bus.