Open FET Sensor - Open-Gate Junction FET Electrometer with extremely low leakage current
The Open FET sensor is a field effect transistor-based sensor in which the gate electrode is connected only to the signal to be measured. Despite the extreme measuring sensitivity, the Open FET sensor is relatively robust. It tolerates input currents of a few 10 μA outside the measuring range and thus protects against electrostatic charges. The Open FET Sensor is particularly well suited for scanning force and scanning tunneling microscopy at low temperatures.
Simple setup
Low cost
High sensitivity
High robustness
many applications
The Open FET sensor offers the possibility to measure small voltages at extremely high impedance. It can be used in scanning force and scanning tunneling microscopy or as an electrometer
The Open FET sensor is a field-effect-based sensor in which the gate electrode is connected only to the signal to be measured and not as usual to other electronic components. By cooling the n-junction FET the leakage current can be reduced to 10-20 A. This means that the Open FET sensor comes very close to an ideal voltage meter. The input capacitance amounts to approx. 5 pF; the full bandwidth is 10 kHz. The input noise is less than 1 µV/√Hz. The left-hand diagram shows the output signal for a square wave signal of 60 μVpp at 3 kHz. Using an integrating mode currents of 10-18 A can be measured, if the bandwidth is reduced. The figure to the right displays the signal at an input current of +/- 1×〖10〗^(-18) A
Licensing
02/11/2016 00:00:00
WO2017EP01274 20171102
- international:
G01Q30/10; H03F1/56
- cooperative:
H03F1/56; H03F2200/261
Patent application
4817
Germany
