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FET-Based Hydrogen

The integrated hydrogen sensor consists of an FET and chemiresistor, both using Pd-Ni metallization, that together measure hydrogen concentrations from 1 ppm to 100%. These sensors are integrated with electronic circuitry for signal processing and temperature control. Applications include detecting hydrogen leaks in rocket engines and refineries, and monitoring corrosion in high-value equipment. As hydrogen cells become more common, hydrogen sensors will be needed in all parts of the fuel cycle from safety to fuel cell performance.

Small, Rugged, And Inexpensive - Overview

A new-generation hydrogen sensor that is smaller, faster, sturdier, and less expensive to manufacture has been developed at Sandia National Laboratories. Early versions of this practical, reliable device for detecting hydrogen already have completed the design, fabrication, and test stages and are now in field application

Existing techniques for detecting hydrogen have numerous drawbacks: limited dynamic range; poor reproducibility and reversibility; subject to false alarms; and tend to be slow, unreliable, and difficult to use.

In comparison, the Sandia sensor provides:

The sensor also exhibits outstanding reproducibility and reversibility and good long term stability. It is manufacturable with standard microelectronics technology and the sensor is simple to use. A broad list of potential applications has been identified, such as:

The sensors were previously used in a multi-point hydrogen leak detection system at NASA's Stennis Space Center (see Figure 1). The sensors also have been used in two field applications -- one in support of environmental monitoring at one of Hanford's waste sites and another involving nuclear reactor safety.

Figure 1
Figure 1.  Multi-point hydrogen leak detection system for the NASA
Stennis Space Center's cryogenic liquids handling technology.

FET-Based Hydrogen Video

Technical Approach

This new technology -- known as the Robust, Wide-Range Hydrogen Sensor (shown in Figures 2 and 3) -- was created by integrating special catalytic alloy films into Sandia's existing complementary metal oxide semiconductor (CMOS) microelectronic technology. The hydrogen sensor uses catalytic palladium nickel (PdNi) gate metallization on field effect transistor sensors for detecting low concentrations of hydrogen (part per million); PdNi resistor sensors for detecting higher concentrations of hydrogen (up to 100%); and on-chip micro-thermometers and micro-heaters for maintaining constant chip temperature (see cross section in Figure 3). Custom control, communication, and other special function electronics can be fabricated on the same small piece of silicon containing the sensor elements. The unique PdNi catalytic alloy used in this project has been patented.

Figure 2



Figure 3

Figure 2.  Sandia's Robust, Wide-Range Hydrogen Sensor overcomes the limitations of existing hydrogen sensing technologies.  Figure 3.   Cross section of Sandia's Robust Wide-Range Hydrogen Sensor, Integration of sensing alloys with the CMOS technology allows fabrication of control electronics on-chip with the sensor elements.

This technology has been exclusively licensed by H2Scan Corporation who can be reached at:

H2scan, LLC
28486 Westinghouse Place, Suite100
Valencia, CA 91355

For additional information or questions, please email us at Biosensors and Nanomaterials

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