Precision PXI source measure unit resolves 10 fA

July 04, 2016 // By Graham Prophet
National Instruments’ PXIe-4135 source measure unit (SMU) has measurement sensitivity of 10 fA and voltage output up to 200V. Engineers can measure low-current signals and cofigure high channel density and fast test throughput in wafer-level parametric test, materials research and characterisation of low-current sensors and ICs.

The module has; a DC source that can drive up to 20W, to 200V or 1A maximum output; 10 fA current sensitivity; triaxial measurement-channel connectors to screen terminations for accurate low-current measurements; 1.8 Msmple/sec maximum sample rate and 100 ksample/sec update rate; NI SourceAdapt technology for fast and stable measurements; and a capacity of up to 17 SMU channels in a 4U, 19 in. PXI chassis.

Engineers can use modular NI PXI SMUs to build parallel, high-channel-count systems in a compact form factor with up to 68 SMU channels in a single PXI chassis that can scale to hundreds of channels to address wafer-level reliability and parallel test. Test throughput is increased by a high-speed communication bus, deterministic hardware sequencing and a digital control loop technology to custom-tune the SMU response for any device under test. Engineers can also control the SMU response through software, which removes unnecessarily long wait times for SMU settling and offers the flexibility to help minimise overshoot and oscillations even with highly capacitive loads.

NI comments that, “Increasing complexity in semiconductor devices requires us to rethink the conventional approach for research, characterisation and reliability measurements, and that’s been a key motivator for our SMU investments in PXI.” A user comment comes from Belgian researchers imec, whose Dr. Bart De Wachter, says, “Our in-line parametric tests require us to acquire millions of data points, often with leakage current in the picoampere range... the PXI SMU allows us to accurately measure these low-current signals [with] speed improvements offered by the PXI platform and the flexibility of programming the system with LabVIEW.”