Semiconductor Device Injection Amount Restricting Portion Breakdown Voltage
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Solution Overview
Problem
Semiconductor devices with deep well regions exhibit low breakdown voltage, particularly in regions occupied by deep well regions compared to diode portions, leading to a large difference in breakdown voltage across the device, which affects overall performance.
Innovation Solution
Incorporating an injection amount restricting portion with a lower second-conductivity-type carrier injection amount per unit area below the well region, utilizing a conductive layer with a higher first-conductivity-type doping concentration than the drift region and a lower second-conductivity-type doping concentration than the collector region, to reduce carrier injection and extend the depletion layer, thereby increasing breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a deep well region is provided below the base region, then the transistor portion can be formed, but the breakdown voltage at that portion becomes low compared to the diode portion
Solution Approach 1:
The patent applies local quality by creating an injection amount restricting portion with specific doping characteristics only in the signal pad region below the well region, while maintaining different doping concentrations in other regions. This localized modification restricts carrier injection specifically where needed without affecting the overall device structure, thereby increasing breakdown voltage at the low-breakdown portion without compromising transistor functionality elsewhere
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
This configuration enhances the breakdown voltage in the signal pad region and reduces the difference in breakdown voltage across the device, improving overall semiconductor device performance and preventing current crowding and heat-related damage.
Implementation Method 1
utilizing a conductive layer with a higher first-conductivity-type doping concentration than the drift region and a lower second-conductivity-type doping concentration than the collector region, to reduce carrier injection and extend the depletion layer, thereby increasing breakdown voltage
Data Source
AI summary
There is provided a semiconductor device including a transistor portion and a diode portion. The transistor portion has a first-conductivity-type drift region formed inside a semiconductor substrate, a second-conductivity-type base region provided above the drift region inside the semiconductor substrate, and a second-conductivity-type collector region provided below the drift region inside the semiconductor substrate. The transistor portion has a second-conductivity-type well region provided inside the semiconductor substrate and extending downward beyond the base region and an injection amount restricting portion occupying at least a part of a region that is positioned below the well region and having a smaller second-conductivity-type carrier injection amount per unit area than the collector region.