Semiconductor Device Field Plate and Thinner Layer for Breakdown Voltage
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Solution Overview
Problem
Nitride semiconductor devices face a decrease in breakdown voltage due to strong electric fields caused by increasing ON current, which existing technologies fail to adequately address.
Innovation Solution
The semiconductor device incorporates a second semiconductor layer with a thinner portion between the source and drain electrodes, along with a field plate electrode that extends from the gate electrode toward the drain, reducing electric field concentration and maintaining high carrier density in areas where fields are unlikely to be concentrated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the ON current is increased, then the power and current handling capability are improved, but the breakdown voltage decreases due to strong electric field concentration
Solution Approach 1:
The patent applies local quality by creating a non-uniform thickness profile in the second semiconductor layer, with a thinner portion positioned beneath the drain electrode and a thicker portion toward the source. This spatial variation in layer thickness locally adjusts the electric field distribution, reducing peak field concentration in critical areas while maintaining overall device performance.
Solution Approach 2:
The patent introduces a dimensional variation by extending the field plate electrode in the lateral direction beyond the gate electrode structure. This extension into the lateral dimension allows the electric field to be managed across a broader spatial area, redistributing the field lines and reducing concentration at critical interfaces.
2Reliability
If a thicker semiconductor layer is used to increase breakdown voltage, then the reliability is improved, but the ON resistance increases
Solution Approach 1:
The patent implements local quality through a thickness-gradient structure in the second semiconductor layer, where the layer transitions from thinner beneath the drain to thicker toward the source. This localized thickness variation optimizes the balance between breakdown voltage (requiring thicker regions) and ON resistance (benefiting from thinner regions), achieving both goals simultaneously in different spatial locations.
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 increases the breakdown voltage while minimizing the increase in ON resistance, effectively addressing the trade-off between ON current and breakdown voltage.
Implementation Method 1
a first field plate electrode provided over the second semiconductor layer and including a portion that extends from a location above the gate electrode toward the drain electrode
Implementation Method 2
maintaining high carrier density in areas where fields are unlikely to be concentrated
Data Source
AI summary
A semiconductor device includes a first semiconductor layer, a second semiconductor layer over the first semiconductor layer, source and drain electrodes over the second semiconductor layer, a gate electrode, and a first field plate electrode. The second semiconductor layer includes a first semiconductor portion and a second semiconductor portion thinner than the first semiconductor portion. The source and drain electrodes are electrically connected to the second semiconductor layer. The gate electrode is provided over the second semiconductor layer between the source electrode and the drain electrode. The first field plate electrode is provided over the second semiconductor layer and includes a portion that extends from a location over the gate electrode toward the drain electrode and has an end portion that is positioned over the second semiconductor portion.