As semiconductor technology continues to advance toward smaller geometries and higher performance, low-leakage measurement at the picoampere (pA) and even femtoampere (fA) levels has become a critical metric for evaluating device performance and reliability. Whether dealing with nanoscale semiconductors, wide-bandgap materials, or organic electronic devices, the precise capture of weak current signals is directly linked to the depth of R&D and the accuracy of production control.

Multi-Faceted Technical Challenges in Low-Leakage Measurement

In the realm of extreme low-current measurement, researchers must contend with several primary sources of interference:

• Environmental Noise: Thermal noise and electromagnetic interference (EMI) are persistent and difficult to completely shield.

• Parasitic Effects: Parasitic capacitance and resistance inherent in test cables and contacts can create unintended current paths. Particularly during high-voltage testing, the charging effect caused by grounding capacitance—compounded by increased RC time constants—can introduce significant measurement errors.

Best Practices for High-Precision Measurement

Taking wafer-level low-leakage testing as an example, achieving high precision and stability requires a systematic approach to the following key areas:

1. Constructing a Low-Noise Detection Environment Utilize a well-shielded measurement space (such as a Faraday cage) to isolate the setup from external electrical noise sources.

2. Suppressing Stray Leakage Current

• Employ fully guarded cables and probes, ensuring the guard layer extends to the probe tip.

• Adopt a wafer chuck with guarding functionality (Guarded Chuck).

Figure: The critical role of guarding technology in low-leakage measurement

3. Optimizing Measurement Parameters

• Select the appropriate measurement range based on the actual signal amplitude.

• Appropriately extend the integration time and the source delay time to stabilize readings.

Figure: The positive impact of increased integration time on reducing noise in low-current tests

4. Implementing Regular Metrology and Calibration

Ensure equipment maintains nominal accuracy over the long term to guarantee data credibility.

Introducing the Nexustest S2035H/S2036H

Nexustest is proud to introduce the S2035H/S2036H High-Precision Benchtop Source Measure Units (SMUs). With current resolution reaching the 1 fA (femtoampere) level, these instruments rank at the forefront of the high-precision measurement market, providing a reliable foundation for frontier scientific research and industrial testing in semiconductors and new materials.

Key Specifications: 

Typical Test Applications

• Nanomaterials and Sensor Testing For emerging materials such as graphene, nanowires, and organic semiconductors, the S2035H/S2036H performs precise I-V sweeps to reveal core parameters including conductivity and carrier mobility.

• Comprehensive Semiconductor Device Characterization Covering a wide range of devices including Diodes, BJTs, MOSFETs, and IGBTs, the series supports full parametric testing. This includes output and transfer characteristics, forward voltage, reverse breakdown voltage, leakage current, threshold voltage, and MOSFET transconductance.

Driving the Industry Forward

The S2035H/S2036H series, achieving 1 fA current resolution, not only resolves ultra-low leakage measurement challenges in nanomaterials and advanced semiconductors but also demonstrates Nexustest' deep expertise in core technical innovation.

Looking ahead, as industries such as 5G, IoT, and AI demand ever-higher device performance, Nexustest remains committed to deepening technical R&D and expanding our product matrix. We are dedicated to providing more precise and reliable measurement solutions for global scientific research and high-end manufacturing, pushing the precision test and measurement industry to new heights.