Overview
IEC 60747-5-16:2023 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies a standardized test method for determining the flat-band voltage of Gallium Nitride (GaN)-based light emitting diodes (LEDs). The technique described leverages photocurrent (PC) spectroscopy to accurately measure the flat-band voltage in single GaN-based LED die or packages that do not include a phosphor. This standard is particularly relevant to manufacturers, researchers, and test laboratories involved in the development and quality assurance of semiconductor LED devices. White LEDs for general lighting, which use phosphor conversion, are not within the scope of this document.
Key Topics
- Flat-Band Voltage Measurement: Defines procedures for measuring the voltage at which the internal electric field across quantum wells in GaN-based LEDs is considered zero.
- Photocurrent Spectroscopy: Details how to use PC spectroscopy - monitoring changes in photocurrent with respect to incident wavelength and applied bias voltage - to identify the flat-band condition.
- Measurement Environment: Specifies essential environmental controls such as temperature (typically 25 ± 3 °C), humidity (25%–75% RH), and thermal equilibrium requirements for reliable measurements.
- Test Setup and Sequence:
- Use of a monochromator, optical chopper, and lock-in amplifier for precise PC spectroscopy.
- Steps for recording and analyzing the spectral radiant flux and spectral photocurrent.
- Sequentially adjusting the bias voltage to identify the maximum peak slope in the differential PC signal, indicating the flat-band voltage.
- Reporting: Outlines the key data and reporting items necessary for documentation and traceability of test results including device identification, environmental conditions, and the measured flat-band voltage.
Applications
IEC 60747-5-16:2023 provides practical guidance for the following:
- Device Characterization: Enables manufacturers and researchers to characterize the electronic properties and performance of GaN-based LEDs, crucial for device optimization and quality assurance.
- Comparative Evaluation: Facilitates benchmarking between different GaN LED structures by providing a consistent basis for flat-band voltage measurement.
- Process Development: Assists in semiconductor process development by offering a quantitative method to monitor and control the internal electric fields of LEDs, impacting efficiency and color performance.
- Research: Supports academic and industrial research into the physics of GaN-based quantum well devices by supplying a reproducible test method.
Related Standards
- IEC 60747-5-6:2021: Semiconductor devices – Part 5-6: Optoelectronic devices – Light emitting diodes. This standard provides general requirements for LEDs and serves as a reference for test methods and equipment.
- IEC 60747-5-15:2022: Semiconductor devices – Part 5-15: Optoelectronic devices – Light emitting diodes – Test method of the flat-band voltage based on electroreflectance (ER) spectroscopy. Offers an alternative optical method for measuring flat-band voltage, useful for comparative studies.
Practical Value
By following IEC 60747-5-16:2023, users benefit from:
- Consistency: Ensures reproducible and reliable flat-band voltage measurements for GaN-based LEDs, supporting product development and quality control.
- Efficiency: PC spectroscopy, as defined by the standard, requires less complex equipment (compared to ER spectroscopy)-no function generator or photomultiplier tube-streamlining laboratory setups.
- Accuracy: Provides a detailed measurement sequence designed to maximize precision and reduce error, enhancing test confidence across the industry.
- Interoperability: Complements other international standards in semiconductor device testing, promoting harmonization and comparability of results within global supply chains.
IEC 60747-5-16:2023 is an essential standard for any organization or laboratory involved with GaN-based LED innovation, testing, and production, driving best practice and reliability in optoelectronic device measurement.
Open preview (PDF)Semiconductor devices - Part 5-16: Optoelectronic devices - Light emitting diodes - Test method of the flat-band voltage of GaN-based light emitting diodes based on the photocurrent spectroscopy
