Keithley 6430 Sub-femtoamp Remote SourceMeter

The Model 6430 Sub-Femtoamp Remote SourceMeter combines the voltage and current sourcing and measurement functions of Keithley’s popular SourceMeter and source measurement unit (SMU) instruments with sensitivity, noise, and input resistance specifications superior to electrometers. This unique combination of broad functionality and exceptional measurement integrity is made possible by the Model 6430’s Remote PreAmp, which offers a very sensitive bi-directional amplifier with sensitive feedback elements for measuring or sourcing currents at the device being tested. The high level signals output by the Remote PreAmp are sent to the controlling mainframe via a two-meter cable. This allows the user to make a direct or very short connection to the signal, minimizing the effects of cable noise.

The Model 6430 makes voltage, current, and resistance measurements at speeds no electrometer can match. It can read up to 2000 source/measure readings per second into internal memory. Currents can be measured in as little as 5ms on the 100nA range, decreasing to just a few hundred microseconds on the higher ranges.

The Model 6430’s distinguishing features include its excellent low current sensitivity and the Remote PreAmp, which makes this sensitivity useful by eliminating long input cables. The Remote PreAmp is an integral part of the Model 6430’s feedback measuring system that cannot be operated independently from the measurement mainframe, although it can be separated from the mainframe by up to two meters of connection cable carrying high level signals.

The Model 6430 provides
four-quadrant sourcing of up to 2.2W,
as well as measurement sensitivity down
to sub-femtoamp and microvolt levels.
It can measure currents from the 1pA
range (with just 0.4fA p-p noise typical)
up to the 100mA range at up to 20V.
Voltage ranges from 200mV to 200V
are available. Current and voltage range
settings define the maximum source or
sink voltage or current.

Applications

The Model 6430’s capabilities make it equally useful for research work and for evaluating sophisticated components in test labs for low-current, high-resistance, or sensitive semiconductor  measurements. The low noise and drift performance of the Model 6430 also makes it well suited for research studies in single electron devices, highly resistive nanowires and nano-tubes, polymers, highly resistive nanomaterials, and electrochemical amperometry applications.

High Speed Data Handling

The Model 6430 can read more than 2000 readings per second into its internal memory buffer. The IEEE-488 bus output can transmit up to 75 source/measure readings per second to an external computer controller, including pass/fail  indication.

Typical applications:
Semiconductor measurements

Gate leakage or channel leakage in FET-based components can generate errors in MOSFETs, JFETs,  analog switches, and many other  circuits. By allowing researchers to measure extremely low-level  currents and voltages, the Model 6430 can help them understand the design limitations of these components and investigate alternative device structures or materials.

SET research

The Model 6430’s superior low current measurement ability (0.4fA p-p noise typical) makes it extremely useful for single electron transistor (SET) and quantum-dot research. Using a technique similar to a lock-in, the 6430 can measure currents with 1aA sensitivity (10 –18 A = 6 electrons/second).

The Measurement Industry’s Lowest Noise and Drift

This data illustrates the Model 6430’s impressive  stability over a five-hour period, as well as its low short-term noise performance. This signal trace was acquired using the instrument’s AUTOFILTER with a 5- second rise time on the 1pA range. The inset close-up is a snapshot of the filtered signal, showing the Model 6430’s low noise during the first 100-second period. The data was taken in a laboratory environment where temperature varied about 1°C, with the instrument’s IN/OUT HI and SENSE leads capped.

Applications:

• Measuring current from optical devices
• Semiconductor testing
• High-resistance measurements