Charge Trap Evaluation in HEMT Devices Using Initialization Voltage
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Solution Overview
Problem
Existing methods for evaluating current collapse in power semiconductor devices, particularly HEMTs, suffer from low measurement reproducibility when using wide bandgap semiconductors with deep trap levels, making it difficult to accurately assess charge trap phenomena.
Innovation Solution
A charge trap evaluation method involving the application of an initialization voltage equal to or greater than the threshold voltage to expel trapped charges, followed by monitoring current changes to evaluate charge capture, current collapse, and charge release, ensuring reproducibility by initializing the trap state before measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vertical voltage is applied to generate current collapse for evaluation, then the collapse due to vertical electric field can be evaluated, but measurement reproducibility is low for wide bandgap semiconductors with deep trap levels
Solution Approach 1:
The patent applies a preliminary action by initializing the trap state through voltage application before performing the current collapse measurement. This preliminary initialization step ensures that trapped charges are in a known state, which resolves the reproducibility issue without compromising the ability to evaluate current collapse accurately.
Solution Approach 2:
The patent employs preliminary anti-action by applying an initialization voltage that expels trapped charges from trap levels before the measurement. This counteracts the random trap state that causes poor reproducibility, creating a consistent starting condition for subsequent measurements while preserving the current collapse evaluation capability.
2Measurement precision
If additional initialization steps like light irradiation or heating are introduced to improve measurement reproducibility, then trap state can be initialized, but device complexity and measurement time increase
Solution Approach 1:
The patent makes the voltage application serve multiple functions: it both initializes the trap state and enables current collapse evaluation. This eliminates the need for separate initialization steps like light irradiation or heating, reducing device complexity while maintaining measurement reproducibility.
Solution Approach 2:
The patent merges the trap state initialization function with the current collapse measurement function into a single voltage application process. By combining these functions, the measurement procedure becomes simpler and requires fewer additional devices or steps.
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 enhances measurement reproducibility for semiconductor devices with deep trap levels, improving the accuracy of current collapse evaluation and reducing production defects by initializing the trap state through voltage application, eliminating the need for additional steps like light irradiation or heating.
Implementation Method 1
a step for applying an initialization voltage having the same sign as a threshold voltage and a magnitude equal to or greater than the threshold voltage between a source electrode and a drain electrode of a semiconductor device having a lateral structure and a substrate of the semiconductor device and initializing a trap state by expelling a trapped charge from a trap level
Implementation Method 2
a step for monitoring a current flowing between the source electrode and the drain electrode after the trap state initialization and evaluating at least one from among charge capture, current collapse, and charge release
Data Source
AI summary
Provided are a charge trap evaluation method and semiconductor device including, in an embodiment, a step for applying an initialization voltage that has the same sign as a threshold voltage and is greater than or equal to the threshold voltage between the source electrode 15 and drain electrode 16 of a semiconductor device 1 having an HEMT structure and the substrate 10 of the semiconductor device 1 and initializing a trap state by forcing out trapped charge from a trap level and a step for monitoring the current flowing between the source electrode 15 and drain electrode 16 after the trap state initialization and evaluating at least one from among charge trapping, current collapse, and charge release.