Calibration of the temperature dependence of the electrical resistance of the metal film as a function of film type and thickness for using the metal film as a temperature measuring device 

Contacts:

Gunver Nielsen, CINF, DTU Physics, PhD student (gunver.nielsen@fysik.dtu.dk)
Lasse B. Thomsen, CINF, DTU Physics, PhD student (lasse.thomsen@fysik.dtu.dk)
Robert Jensen, CINF, DTU Physics, PhD student (Robert.jensen@fysik.dtu.dk
Ib Chorkendorff, CINF, DTU Physics, 4525-3170 (ibchork@fysik.dtu.dk)

http://www.cinf.dtu.dk/~s001610

Upper: Hot Electrons are tunneling into both the elements in the array of hot electron emitters. Lower: The oxide under the right element is broken down and the increased current has led the two nano-fuses to disconnect the connection to the rest of the array to avoid drawing excess current through the array.

At CINF we are working with hot electron devices, which are Si-SiO₂-Metal sandwiches which are capable of emitting electrons either into the top metal film or into the vacuum. The electrons are emitted by setting a bias between the Si-layer and the metal layer which causes electrons to tunnel through the SiO₂ -layer. When emitting electrons into the vacuum, some spatial distribution of the emittance is unavoidable due to both small impurities in the device and to the finite electrical resistance of the metal film which causes a voltage drop across the film and thus a gradient in the intensity of electrons.

In this project we would like you to examine the possibility of using the resistance for measuring the temperature of the sample. Using traditional temperature measurement techniques (like thermocouples and conventional RTDs) you will correlate the temperature of the sample to the resistance of the metal film. Ideally this should be done using a four-point probe, which eliminates the contact resistance, but since four point measurements are not always possible in UHV (where the technique is ultimately to be used) we need to know if a two point measurement is sufficient. You will need to experiment with different metal types and thicknesses in order to establish whether the resistance can reliably be calibrated to measure the temperature in all circumstances or if it turns out to be necessary to calibrate every single film to get a good measure of the temperature.