Vertical Trench Transistor Sensing for Fast Drain Potential Transients
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Solution Overview
Problem
Vertical transistor devices face challenges in sensing fast transients in drain-to-source voltage, which can lead to dynamic avalanches and return-on events, causing potential failure or degradation, due to the lack of effective mechanisms for detecting and mitigating these rapid potential changes.
Innovation Solution
Incorporating a sense electrode contact spaced apart from the control electrode contact for the first trench electrode, allowing it to be used capacitively for sensing variations in drain potential, thereby enabling the detection of fast transients and allowing for countermeasures to prevent device failure, while the trench electrode is used both for channel creation and field shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate sense electrode is added beside the transistor device for sensing backside potential, then sensing capability is improved, but device area increases
Solution Approach 1:
The first trench electrode is designed to serve dual functions: it acts as an active electrode for channel creation or field shaping in the vertical transistor device, and simultaneously serves as a sense electrode for capacitively sensing backside potential variations. This multi-functionality eliminates the need for a separate sense electrode, thereby maintaining sensing capability while reducing device area.
Solution Approach 2:
The sensing function is merged with the existing first trench electrode structure. By adding a sense electrode contact spaced apart from the control electrode contact to the same first trench electrode, the patent combines the active electrode and sense electrode into a single structural element, achieving area reduction while preserving both transistor operation and sensing capabilities.
2Area of stationary object
If the first trench electrode is used for both active function and sensing, then area is reduced, but sensing accuracy may be affected by internal resistance
Solution Approach 1:
The first trench electrode is segmented into two functionally distinct contact points: a control electrode contact for applying the active electrical potential and a sense electrode contact for sensing. By spacing these contacts apart laterally, the patent creates separate access points that allow the same physical electrode to perform both active and sensing functions with minimal interference between the two operations.
Solution Approach 2:
The lateral separation distance between the control and sense electrode contacts acts as an intermediary element. This spatial separation allows the sense contact to probe potential variations without being directly influenced by the potential applied at the control contact, thereby maintaining sensing accuracy while using the same electrode structure.
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 setup allows for the effective sensing of backside potential variations and transients, enabling proactive measures to prevent device failure by using the active electrode within the trench as a capacitor, reducing the need for separate sense electrodes and allowing for area reduction, thus enhancing the reliability of the vertical transistor device.
Implementation Method 1
the first trench electrode can be used as a first capacitor electrode which forms a capacitor together with a second capacitor electrode disposed at the second side of the semiconductor body, in particular with the drain region in case of a common drain backside
Data Source
AI summary
A semiconductor die with a semiconductor body includes a transistor device having: a source region at a first side of the semiconductor body; a drain region at a second side of the semiconductor body; a trench extending from the first side into the semiconductor body and having an elongated lateral extension; a first trench electrode configured for channel creation or field shaping, having an elongated lateral extension, and disposed in the trench; and a control electrode contact contacting the first trench electrode from the first side and configured to apply an electrical potential, the control electrode contact disposed at a first lateral position. A sense electrode contact contacting the first trench electrode from the first side is configured to sense a voltage from the first trench electrode. The sense electrode contact is disposed at a second lateral position which is spaced from the first lateral position.