Semiconductor Device Charge Extracting Region Inhibits Parasitic Bipolar Transistor
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Solution Overview
Problem
High breakdown voltage ICs face challenges in inhibiting the operation of parasitic bipolar transistors, particularly in high-side driving circuits, due to noise-induced voltage surges, which can lead to malfunction and heat generation from large currents.
Innovation Solution
The semiconductor device incorporates a first well region of one conduction type and a second well region of a different conduction type, along with a charge extracting region of the first conduction type, to inhibit the operation of parasitic bipolar transistors by applying voltages in a manner that biases a p-i-n diode forward, allowing current extraction and reducing parasitic transistor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high breakdown voltage IC is used for power conversion, then power conversion capability is improved, but parasitic bipolar transistor operation occurs due to noise-induced voltage surges
Solution Approach 1:
A charge extracting region is introduced as an intermediary element between the n-well region and the p-type semiconductor substrate. This region acts as a mediator to extract accumulated charges that would otherwise trigger parasitic bipolar transistor operation, thereby resolving the contradiction between maintaining high breakdown voltage for power conversion and preventing parasitic transistor activation from noise-induced voltage surges
2Power
If the longitudinal area of the high-side region is increased to handle higher currents, then power conversion efficiency is improved, but parasitic element operation becomes more likely due to larger area
Solution Approach 1:
The charge extracting region is locally positioned within the high-side region's longitudinal area, specifically in the n-well region. This local modification allows the high-side region to maintain its large longitudinal area for high current handling capability, while the locally introduced charge extracting region selectively addresses the harmful parasitic element operation by extracting accumulated charges in that specific location
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 effectively reduces the current flowing into parasitic pnp bipolar transistors, preventing malfunctions and enhancing the reliability of the semiconductor device by maintaining a breakdown voltage and inhibiting parasitic transistor operation.
Implementation Method 1
applying voltages in a manner that biases a p-i-n diode forward, allowing current extraction and reducing parasitic transistor operation
Data Source
AI summary
A semiconductor device is provided with a first well region of a first conduction type having a first voltage (voltage VB) applied thereto, a second well region of a second conduction type formed in the surface layer section of the first well region and having a second voltage (voltage VS) different from the first voltage applied thereto, and a charge extracting region of the first conduction type formed in the surface layer section of the second well region and having the first voltage applied thereto. This inhibits the operation of a parasitic bipolar transistor.