Diode Assembly with Adjustable Trigger Voltages
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Solution Overview
Problem
Existing semiconductor circuit protection methods, such as diode chains in forward or reverse biased configurations, face challenges in compactness and flexibility in setting trigger voltages for electrostatic discharge (ESD) protection, with forward biased configurations being large and reverse biased configurations having fixed trigger voltages determined by intrinsic diode properties.
Innovation Solution
A diode assembly comprising two diodes with different breakdown voltages, each with a semiconductor substrate, an electrically conducting channel layer, and a recess with a gate electrode, where the area covered by the gate electrode differs between the diodes, allowing for adjustable trigger voltages during manufacturing by varying the distance between the gate and recess edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If forward biased diode chain configuration is used, then trigger voltage can be scaled by number of diodes, but device area becomes large
Solution Approach 1:
The patent changes the operating parameter from forward bias to reverse bias configuration, and further modifies the breakdown voltage parameter through geometric adjustments (gate width, gate-to-recess distance) to achieve scalable trigger voltages without increasing device area. This allows trigger voltage scaling while maintaining compact dimensions.
2Area of stationary object
If reverse biased diode configuration is used, then device area is reduced, but trigger voltage becomes fixed by intrinsic properties
Solution Approach 1:
The patent applies local quality by making specific geometric parameters (gate width Wg, gate-to-recess distance d) different for each diode in the chain. This allows each diode to have a tailored breakdown voltage while maintaining the same compact reverse-biased structure, enabling adjustable trigger voltages without increasing overall device area.
Solution Approach 2:
The patent modifies the breakdown voltage parameter through geometric adjustments (gate width, gate-to-recess distance) rather than relying on intrinsic material properties. This enables scalable and adjustable trigger voltages while maintaining the compact reverse-biased configuration.
3Adaptability or versatility
If gate-to-recess distance is reduced, then breakdown voltage decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses geometric parameter changes (gate width Wg, gate-to-recess distance d) to control breakdown voltage. While this provides adjustable trigger voltages, it inherently requires precise manufacturing to achieve the desired breakdown voltage characteristics.
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
The solution provides a compact diode assembly with adjustable trigger voltages, enabling tailored ESD protection in semiconductor circuits while maintaining a compact design, allowing for flexible integration in integrated circuits.
Implementation Method 1
When a negative voltage is applied to the gate 8 current flow between the source 22 and drain 23 is blocked
Implementation Method 2
the area of the recess of the first diode covered by the first gate electrode is different to the area of the recess of the second diode covered by the second gate electrode
Data Source
AI summary
A diode assembly comprising first and second diodes each having a different breakdown voltage, each of the first and second diodes comprising a semiconductor substrate; an electrically conducting channel layer on the semiconductor substrate; an upper semiconductor layer on the channel layer, the upper semiconductor layer comprising a recess; first and second ohmic contacts on the upper semiconductor layer on opposite sides of the recess, the ohmic contacts being connected together to form a first diode contact; a gate electrode within the recess, the gate electrode forming a second diode contact; wherein the area of the recess of the first diode covered by the first gate electrode is different to the area of the recess of the second diode covered by the second gate electrode.