Making Low Current (Femtoampere Level) Measurements?

The Micromanipulator Company has established an excellent reputation by not only selling the industry’s best state-of-the-art probe stations but making it a priority to help our customers’ succeed by providing useful information.  One area we feel it important for both beginners and experienced user to have more details available is when using a probe station to make low current (femtoampere level) measurements.   

While our engineers are ready to help customers use our tools effectively, our Basics of Low Current Probing application note concisely and clearly goes over the required steps for the proper setup, shielding and guarding.  In addition the equipment needed to provide the correct probing environment is described along with many of the common problems users encounter and the best ways to solve them.  By elaborating on the many factors that can adversely affect low level measurements, it gives users a better chance to identify and minimize the noise source or the noise coupling mechanism and to learn how to isolate noise from the signal.  

Here you will a description of the two typical probe contact configurations used in the grounding and shielding techniques for low current measurements.  The first configuration is surface to surface and is represented by MOSFET subthreshold measurements.  The second one is defined as surface to substrate measurements and represented by time dependent dielectric leakage observations (TDDL).  Our note contains figures of these configurations to make it easier to understand.  The note also discusses the issue of cable isolation and noise.   

Micromanipulator’s Basics of Low Current Probing guidelines for successful low level measurements remind users to pay attention to details.  As you will discover many factors can interfere with the desired measurement because of the very small physical values being observed.  Our recommendation is to review and practice the prevention measures provided to help eliminate problems before they occur.  Another tip to avoid problems is to keep your probe station clean.  Please visit our website to read the complete application note as well as take a look at our many products.   

Micromanipulator not only invented analytical probing in 1956 but we remain the leading name in the field.  As such we reliably deliver the tools and life cycle support the semiconductor industry depends on.  As part of our company’s philosophy and what drives our success is an unfaltering commitment to customers’ satisfaction.  We invite you to contact us to find out more about our wide range of probe stations, accessories and consumables.