Non-linear Dielectric Field Plate for Semiconductor Reliability
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Solution Overview
Problem
Existing field plate semiconductor devices face challenges in balancing electric field distribution and leakage current reduction, as increasing permittivity of dielectric materials can lead to semiconductor damage under high voltage, while reducing insulation layer thickness increases manufacturing difficulties and breakdown risk.
Innovation Solution
Employing a non-linear dielectric material with varying permittivity based on electric field strength, such as strontium-bismuth titanate, which has high permittivity at low electric fields and low permittivity at high electric fields, to optimize electron gas depletion and enhance semiconductor device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric material with higher permittivity is chosen to increase the capacitance of the insulating layer, then the electron gas depletion and leakage current reduction is improved, but the electric field in the semiconductor layers increases leading to potential breakdown and degradation
Solution Approach 1:
The patent applies local quality by using a first dielectric material with high permittivity in the region where electron gas depletion is needed (under the field plate), while using a second dielectric material with low permittivity in regions where electric field reduction is critical (near semiconductor interfaces). This spatial differentiation of dielectric properties allows simultaneous achievement of high capacitance for leakage reduction and low electric field for damage prevention.
Solution Approach 2:
The patent employs composite materials by combining two different dielectric materials with contrasting permittivity characteristics. The insulating layer is formed as a composite structure where the first dielectric material (high permittivity) and second dielectric material (low permittivity) are strategically positioned to create a multi-functional insulating system that addresses both contradictory requirements.
2Speed
If the thickness of the insulation layer is reduced to increase its capacitance, then the electron gas depletion speed is improved, but the manufacturing difficulty increases and the breakdown voltage decreases
Solution Approach 1:
The patent applies parameter changes by modifying the dielectric permittivity parameter rather than the geometric thickness parameter. By selecting dielectric materials with appropriately high permittivity values, the patent achieves the desired capacitance increase without reducing the physical thickness of the insulating layer, thereby maintaining manufacturability and breakdown voltage while still enabling fast electron gas depletion.
3Loss of time
If the thickness of the insulation layer is reduced to increase its capacitance, then the turn-off speed of the diode is improved, but the breakdown voltage of the insulation layer decreases increasing damage risk
Solution Approach 1:
The patent uses composite dielectric materials to simultaneously achieve fast turn-off and high breakdown resistance. The first dielectric material with high permittivity provides the capacitance needed for rapid electron gas depletion and fast turn-off, while the second dielectric material with low permittivity and high breakdown strength provides the structural integrity and voltage withstand capability, creating a composite insulating layer that satisfies both speed and reliability requirements.
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 approach allows for faster electron gas depletion with reduced parasitic leaks and improved breakdown protection, while maintaining a thin insulation layer for efficient operation and easier manufacturing.
Implementation Method 1
Employing a non-linear dielectric material with varying permittivity based on electric field strength, such as strontium-bismuth titanate, which has high permittivity at low electric fields and low permittivity at high electric fields
Implementation Method 2
The field plate allows for a better distribution of the electric field in order to avoid electric field peaks that could damage the semiconductor device 100
Implementation Method 3
Another effect of the field plate is the depletion of the electron gas when diode 100 is reverse-biased. This depletion reduces the leakage current of the reverse-biased diode 100
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a semiconductor device (200) comprising: - a substrate; - a semiconductor structure disposed on the substrate, the semiconductor structure comprising at least a first semiconductor layer (201); - an insulation layer (207) disposed on the semiconductor structure; - a field plate (208) covering a part of the insulation layer (207); the semiconductor device (200) being characterized in that the insulation layer (207) comprises a non-linear dielectric material having a permittivity which decreases as an electric field through the dielectric material increases.