Bipolar Transistor Base Segmentation for Voltage Resistance
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Solution Overview
Problem
Bipolar transistors with a base region between the collector and emitter regions face a trade-off between voltage resistance and current amplification rate, where long distances between these regions improve voltage resistance but decrease current amplification due to increased carrier movement distances.
Innovation Solution
A bipolar transistor design featuring a semiconductor substrate with a p-type or n-type base region between the collector and emitter regions, and p-type or n-type embedded regions with lower impurity concentrations, where the base region projects out towards the collector or emitter side, reducing carrier loss and depletion, and optionally including additional embedded regions to further enhance current amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the distance between the collector region and the emitter region is increased to improve voltage resistance, then the voltage resistance is improved, but the current amplification rate decreases due to increased carrier movement distance
Solution Approach 1:
The invention introduces an embedded region that divides the base region into two separate base regions. This segmentation allows carriers to traverse shorter distances in each segment while maintaining the overall long distance between collector and emitter for voltage resistance, thereby resolving the contradiction between voltage resistance and current amplification rate
Solution Approach 2:
The embedded region extends in the depth direction (vertical dimension) beneath the base region, creating a three-dimensional structure. This dimensional change allows carriers to move through the embedded region which has different electrical properties, effectively reducing the carrier movement path while maintaining the horizontal distance for voltage resistance
2Strength
If the base region is made wider to improve voltage resistance, then the voltage resistance improves, but the turn-on time increases due to longer carrier transit time
Solution Approach 1:
By dividing the base region into two segments through the embedded region, the carrier transit time across each segment is reduced. This segmentation maintains the overall width for voltage resistance while decreasing the effective transit distance for carriers, thus reducing turn-on time
Solution Approach 2:
The embedded region has different impurity concentration parameters compared to the base region. By changing the electrical parameters (impurity concentration) in the embedded region, the carrier mobility and transit time are optimized, allowing longer base width for voltage resistance without proportionally increasing turn-on time
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 improves both voltage resistance and current amplification rate by minimizing carrier loss and depletion, while shortening turn-on time and reducing heat generation.
Implementation Method 1
an n-type region having a lower n-type impurity concentration than the base region, being in contact with the emitter region, the collector region, the base region and the first embedded region, separating the emitter region from the base region and the first embedded region, and separating the collector region from the base region and the first embedded region
Implementation Method 2
a depletion layer generated between the collector and the base when the bipolar transistor is turned off can be suppressed from reaching the first embedded region
Data Source
AI summary
Disclosed herein is a bipolar transistor capable of improving a current amplification rate while improving voltage resistance. A bipolar transistor is provided with a p-type emitter region, a p-type collector region, an n-type base region located between the emitter region and the collector region, a p-type first embedded region located below the base region, and an n-type region having a lower n-type impurity concentration than the base region, being in contact with the emitter region, the collector region, the base region and the first embedded region, separating the emitter region from the base region and the first embedded region, and separating the collector region from the base region and the first embedded region. A part of the base region projects out toward a collector region side than the first embedded region does.