Extremely low-noise JFETS for the gigahertz range


© Fraunhofer EMFT
Silicon wafer with low-noise JFETs, showing the microscope image of the chip in the background

The aim of the internal Fraunhofer project "Low-Noise" is to advance development of new, extremely low-noise FET transistors and adapt them to the specific requirements of potential customers. The advantage of the low-noise JFET is that it reaches a cut-off frequency of 1GHz – making it the »fastest« silicon-based JFET to date as compared to commercial products. In X-ray fluorescence applications, Fraunhofer EMFT's low-noise JFETs take half the time to measure the same spectral resolution as transistors currently available on the market. What is more, the low-noise JFETs work at room temperature, so cooling is not necessary. This significantly simplifies assembly of the sensor as well as reducing both cost and power consumption.

Further optimization in the areas of robustness, limit frequency and noise will seek to reduce measuring time even further. In the medium term, this concept could potentially also be used in high-frequency oscillators and mixers.


The project is being funded under the internal Fraunhofer program MEF.