IGBT Contact Area Ratios for Lateral Device Optimization
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Solution Overview
Problem
Developing semiconductor devices with multiple lateral Insulated Gate Bipolar Transistors (IGBTs) on the same chip is challenging due to differing requirements for current and breakdown voltage, which necessitates substantial changes and optimizations, increasing development burden.
Innovation Solution
A semiconductor device configuration with varying ratios of contact areas for the base and collector regions in each IGBT, allowing for adjustments in device characteristics without drastic changes, such as altering device size or impurity injection layouts, by optimizing the contact area ratios between the emitter and base, and collector regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substantial changes are made to device size, impurity injection layout, and impurity injection condition to improve current and breakdown voltage characteristics, then the characteristics of lateral IGBTs are improved, but the development burden increases significantly
Solution Approach 1:
The patent changes the geometric parameters of the contact regions (base region contact area ratio and collector region contact area ratio) rather than making substantial changes to device size or impurity injection conditions. By adjusting these contact area ratios, the patent achieves different characteristics for current-oriented and breakdown voltage-oriented IGBTs using the same basic device structure and impurity injection parameters, thereby reducing development burden while improving characteristics
2Adaptability or versatility
If different lateral IGBTs are placed on the same chip with different characteristics requirements, then chip functionality is enhanced, but it becomes difficult to meet different requirements with a single device structure
Solution Approach 1:
The patent applies local quality by creating different contact area ratios for base and collector regions in different IGBTs on the same chip. Specifically, the first lateral IGBT has a first base region contact area ratio and a first collector region contact area ratio, while the second lateral IGBT has a second base region contact area ratio and a second collector region contact area ratio. This allows each IGBT to be optimized for its specific function (current or breakdown voltage) while using the same overall device structure and manufacturing process
3Reliability
If device size is changed to improve characteristics, then current and breakdown voltage are improved, but the device structure requires substantial modification
Solution Approach 1:
Instead of changing device size substantially, the patent changes the contact area ratios of existing regions. The base region contact area ratio is defined as the ratio of the contact area between the base region and the semiconductor substrate to the total area of the base region, and similarly for the collector region. By adjusting these ratios, the patent achieves characteristic optimization without modifying the fundamental device structure or dimensions
Data Source
AI summary
In a semiconductor device, at least one of the ratio (collector contact area/collector active area) in the High Side IGBT and the ratio (contact area on p+ region/p+ region area) is higher than the ratio in the Low Side IGBT. Thus, it is possible to develop without substantial changes and reduce the development burden.