Application Cases

Experiment Name: Non-Destructive Testing of LED Epitaxial Wafers Based on the Single-Ended Contact Principle

Experiment Content:Based on the single-injection mode, a novel detection system is used to obtain the electrical and optical parameters of LED epitaxial wafers.

Research Direction: Detection of LED Epitaxial Wafers

Testing Equipment:Spectrometer, function signal generator, ATA-2161 high-voltage amplifier, microscope and imaging system, oscilloscope, computer, etc.

Experimental Process:

Figure 1: Schematic Diagram of the Experimental Setup

Firstly, photoluminescence (PL) testing is conducted on the LED epitaxial wafer to obtain the peak wavelength through the spectrometer. Then, after connecting the test equipment as shown in Figure 1, the LED epitaxial wafer to be tested is placed on the ITO glass. The probe is slowly lowered until the LED epitaxial wafer exhibits electroluminescence. The peak wavelength is obtained through the spectrometer, and the electrical parameters are obtained through the oscilloscope. Finally, traditional electroluminescence (needle testing) is used to test the LED epitaxial wafer. The electrical and optical parameters of the LED epitaxial wafer are obtained while ensuring that the relative intensity displayed by the spectrometer software is consistent or close.

Experimental Results:

Figure 2: Optical Parameters Obtained by SC-EL vs. Optical Parameters Obtained by Needle Testing

Figure 3: Optical Parameters Obtained by SC-EL vs. Optical Parameters Obtained by Needle Testing

Since the data obtained by needle testing is the most reliable, it is used as the standard value to compare the accuracy of the data obtained by PL testing and single-ended contact electroluminescence (SC-EL) testing. The experimental results show that the optical parameters obtained by SC-EL are closer to those obtained by needle testing and do not cause mechanical damage to the LED epitaxial wafer (as shown in Figures 2 and 3). In addition, the electrical parameters obtained by SC-EL have the same trend as those obtained by needle testing (reverse leakage current), which can reflect the level of the data obtained by needle testing (as shown in Figure 4).

Figure 4: The Level of Data Obtained by Needle Testing

High-Voltage Amplifier Recommendation: ATA-2161

Figure: Performance Parameters of the ATA-2161 High-Voltage Amplifier

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