Semiconductor Substrate Potential Control for Parasitic Element Prevention
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Solution Overview
Problem
In semiconductor devices with both power and circuit elements formed on the same substrate, negative current flow can cause the potential of the semiconductor substrate to become lower than the deep p-type semiconductor layer, activating parasitic elements and leading to device malfunction.
Innovation Solution
Incorporating an external circuit with a resistive element and a diode connected to the semiconductor substrate and layer, which maintains the potential of the semiconductor layer at a higher value than the substrate, preventing the activation of parasitic elements by ensuring the substrate potential remains non-negative even during negative current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power element and circuit element are formed in the same semiconductor substrate, then device integration is improved, but parasitic element activation occurs during negative current flow
Solution Approach 1:
A potential control circuit is introduced as an intermediary between the semiconductor substrate and the external environment. This control circuit includes a resistive element connected between the semiconductor substrate and a power supply, and a diode connected between the control circuit and ground. The control circuit acts as a mediator that actively manages the substrate potential to prevent parasitic element activation while maintaining the integrated structure.
Solution Approach 2:
The invention dynamically changes the electrical potential parameter of the semiconductor substrate through the potential control circuit. By adjusting the substrate potential to remain higher than the deep p-type semiconductor layer potential during negative current flow, the circuit prevents the voltage conditions that would activate parasitic elements, thus resolving the reliability issue while maintaining integration.
2Power
If substrate potential is allowed to drop during negative current flow, then current conduction is improved, but parasitic current flows from p-type layer to substrate
Solution Approach 1:
The potential control circuit applies preliminary anti-action by proactively preventing the substrate potential from dropping below the deep p-type semiconductor layer potential. The resistive element and diode configuration ensures that even during negative current flow, the substrate potential is maintained at a level that prevents parasitic current flow, countering the harmful effect before it can occur.
Solution Approach 2:
The diode connected between the control circuit and ground provides a feedback mechanism that monitors and regulates the substrate potential. When the substrate potential approaches levels that could activate parasitic elements, the feedback path through the diode activates to prevent further potential drops, thus preventing parasitic current while allowing necessary current conduction.
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 prevents parasitic element operation, thereby preventing device malfunction and extending the semiconductor device's operational lifespan by maintaining stable potential differences.
Implementation Method 1
a first diode having an anode electrode connected to the other end of the first resistive element and a cathode electrode connected to a ground
Data Source
AI summary
Even in the case where negative current flows in a semiconductor device, the potential of a semiconductor substrate is prevented from becoming lower than the potential of a deep semiconductor layer which is a component of a circuit element, and a parasitic element is prevented from operating, which accordingly prevents malfunction of the semiconductor device. The semiconductor device includes the n-type semiconductor substrate, a power element, the circuit element, and an external circuit. The external circuit includes a power supply, a resistive element having one end connected to the power supply, and a diode having its anode electrode connected to the other end of the resistive element and its cathode electrode connected to the ground. To the other end of the resistive element, a semiconductor layer is connected.