GaN Semiconductor Defect Density Evaluation via Current Measurement
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Solution Overview
Problem
Existing methods struggle to accurately evaluate the electrical defect density in semiconductor layers, particularly for wide bandgap semiconductors with deep trap levels, as they fail to effectively monitor electrons and holes trapped in these levels.
Innovation Solution
A method involving the measurement of electric current through a semiconductor layer by applying voltage, where the electrical defect density is derived using current values on both low and high potential sides, allowing for the evaluation of semiconductor elements with low defect densities and deep defect levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a CV curve method is used to derive carrier density, then the measurement is simple and quick, but it cannot effectively monitor electrons and holes trapped in deep trap levels
Solution Approach 1:
The patent changes the measurement parameter from voltage (CV method) to current (I-V method). By measuring current at multiple voltage points and deriving defect density from current values, the method can detect deep trap levels that are invisible to conventional voltage-based CV measurements, thus improving measurement precision without significantly increasing time loss.
2Ease of operation
If conventional CV curve method is applied, then the evaluation process is straightforward, but it fails to evaluate electrical defect density in wide bandgap semiconductors with deep defect levels
Solution Approach 1:
The patent transitions from voltage-based CV measurement to current-based I-V measurement. This parameter change enables the method to adapt to wide bandgap semiconductors with deep defect levels, as current measurements can capture carrier trapping and de-trapping processes that voltage measurements miss, thereby improving versatility while maintaining operational simplicity.
3Device complexity
If deep trap levels are not monitored, then the measurement process remains simple, but the electrical defect density evaluation is incomplete and inaccurate
Solution Approach 1:
The patent segments the measurement process into multiple voltage points (low potential side and high potential side) to separately capture carrier behavior at different energy levels. This segmentation allows detection of deep trap levels by comparing current values at different voltages, improving defect density accuracy without requiring complex single-step measurement equipment.
Solution Approach 2:
The patent performs measurements at multiple voltage points beyond what a single CV measurement provides. By measuring current at both low and high potential sides and using the difference, the method obtains excessive information about carrier trapping that enables accurate deep defect level detection, justifying the increased measurement steps through improved precision.
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 method enables the precise evaluation of electrical defect density in wide bandgap semiconductors, facilitating the production of reliable semiconductor devices by quantifying charge accumulation and defect distribution within the semiconductor layer.
Implementation Method 1
a step for measuring an electric current by applying a voltage to a semiconductor layer
Data Source
AI summary
One embodiment of the present invention provides a method for evaluating the electrical defect density of a semiconductor layer, which comprises: a step for measuring an electric current by applying a voltage to a semiconductor element 1 which comprises a GaN layer 12 that serves as a semiconductor layer; and a step for deriving the electrical defect density in the GaN layer 12 with use of the measured electric current value.