Specific Process Knowledge/Characterization/XPS

XPS-ThermoScientific

A X-ray Photoecectron Spectroscopy (XPS) system can be used at Danchip. The system is a Thermo K-Alpha system, and is found in LabManager under the name XPS-ThermoScientific.

Elemental analysis

The XPS technique can be used to do elemental analysis. A comparision about techniques and intsrumens used for elemental analysis at Danchip can be found on the page Element analysis.

XPS technique

XPS is a surface sensitive and non destructive technique used for elemental composition analysis.

In the XPS spectrometer system the probed samples are irradiated by photons with a specific energy, and the photoelectrons that leaves the sample are detected. The energy levels of the electrons are elemental specific, and by measuring the energy of the outgoing electrons, it is possible to detect which elements that are present in a sample.

XPS Si2p spectrum of Si sample

Stochiometry as a function of film depth (etch time). The relationship between Cr and Ni is quite stabel through the film. Measurements done with XPS-ThermoScientific

A rough overview of XPS-ThermoScientific characteristics

Purpose	Chemical analysis	Probing elemental composition Chemical state identification Non destructive technique Surface sensitive Depth profiling possible by ion beam etch of sample
Performance	Spot size	Can be set between 30µm - 400µm
	Probing depth	Depending on probed element. Max probe depth lies within 10-200 Å.
	Resolution	Dependent on probed elements. Concentrations down to about 0,5 atomic % can in some cases be detected.
	Charge compensation	Flood gun can be used for charge compensation of non conductive samples
	Finding structures	Choose measuring spot from camera image (magnified)
Depth profiling	Purpose	With ion beam etch the top layer of the material can be removed, to do a depth profiling
	Ion beam size	About 0,3x1 mm
Substrates	Substrate size	Max 60x60 mm
	Substrate thickness	Max height about 20 mm