Bipolar Transistor Collector Layer Schottky Protection Diode Integration
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Solution Overview
Problem
Existing semiconductor devices face challenges in miniaturization while effectively protecting bipolar transistors from overvoltage due to the separate integration of protection diodes, which increases device size and complexity.
Innovation Solution
A semiconductor device design that integrates a bipolar transistor and a protection diode on a shared semiconductor substrate, where the collector layer of the bipolar transistor also functions as the semiconductor layer for the protection diode, allowing for a compact configuration with Schottky junctions between the collector and base or emitter, thereby minimizing space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection diode is separately integrated from the bipolar transistor, then the protection function is ensured, but the device size increases
Solution Approach 1:
The patent merges the protection diode and bipolar transistor into a single integrated structure where the collector layer serves dual purposes: as the collector for the bipolar transistor and as the semiconductor layer for the protection diode. This integration eliminates the need for separate protection diode structures, thereby reducing device size while maintaining protection functionality.
Solution Approach 2:
The collector layer is designed to perform multiple functions simultaneously: it acts as the collector region for the bipolar transistor and as the active semiconductor layer for the protection diode. This multi-functionality allows the same structural element to provide both transistor operation and overvoltage protection, reducing the overall device footprint.
2Reliability
If additional semiconductor layers are added for protection diode, then protection capability is enhanced, but device complexity increases
Solution Approach 1:
The patent combines the protection diode structure with the bipolar transistor structure by using the collector layer as a shared component. This merging approach eliminates the need for additional separate semiconductor layers that would otherwise be required for a discrete protection diode, thereby reducing structural complexity while preserving protection capability.
Solution Approach 2:
The collector layer is designed to serve dual functions: as the collector for the bipolar transistor and as the semiconductor layer for the protection diode. This multi-functional design eliminates the need for additional dedicated layers for protection, simplifying the overall device structure while maintaining robust protection capability.
3Area of stationary object
If protection diode is integrated using shared collector layer, then device size is reduced, but parasitic resistance may increase
Solution Approach 1:
The patent applies local quality by forming a Schottky junction specifically in a partial region of the upper surface of the collector layer, rather than across the entire surface. This localized Schottky contact minimizes the impact on the bipolar transistor's current flow paths while still providing effective protection diode functionality, thereby controlling parasitic resistance.
Solution Approach 2:
The Schottky electrode is positioned to contact only a portion of the collector layer surface, creating the protection diode function in a localized area. This partial action approach ensures that the protection function is achieved without unnecessarily increasing parasitic resistance in the main transistor operation regions, balancing miniaturization with performance.
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 design achieves miniaturization of semiconductor devices by eliminating the need for additional semiconductor layers for protection diodes, enhancing protection against overvoltage while reducing parasitic resistance and maintaining performance.
Implementation Method 1
a first Schottky electrode that forms, in a partial region of an upper surface of the collector layer, a Schottky junction to the collector layer
Data Source
AI summary
A semiconductor device includes a sub-collector layer disposed on a substrate, a bipolar transistor including a collector layer formed of a semiconductor having a lower carrier concentration than the sub-collector layer, a base layer, and an emitter layer, and a protection diode including a Schottky electrode. The Schottky electrode forms, in a partial region of an upper surface of the collector layer, a Schottky junction to the collector layer and is connected to one of the base layer and the emitter layer. In the collector layer, a part that forms a junction to the base layer and a part that forms a junction to the Schottky electrode are electrically connected to each other via the collector layer.