Characterization

Electrical

The electrical characterization of devices and circuits is unthinkable without sound measuring techniques and methods. At Namlab we have a broad spectrum of electrical measuring methods for the analysis of devices at our disposal. These start with capacity measurements, such as C(U), C(T) and C(f), through to current measurements in the femtoampere range for temperature between 70K and 450K. The established methods available at Namlab include:

Analytical measurements of single memory cells (NVM, PRAM ) for the determination of lifetime, storage and deletion windows as well as switch time.

Determination of transistor and capacitor characteristic curves.

Measurement of charge carrier flexibility with Hall and split-C(U).

Determination of layer resistance.

Scanning spreading resistance microscopy .

Reliability measurements of dielectric and transistors, starting with time-dependent dielectric breakdown and stress induced leakage current all the way to bias temperature instability and hot carrier injection. For those methods a “most likely” analysis is available.

Charge pumping and charge trapping analysis.

The available methods can be applied to wafers or to devices mounted in a package. This is done with 200nm and 300nm measuring stations such as Keithley and Agilent. The know-how and the technical devices are employed and continuously developed in numerous research and collaboration projects.

Physical and optical

Optical characterization methods are available at Namlab that cover the entire wavelength range from 250 nm in the ultraviolet to the infrared wavelength of 17 µm. These include techniques such as:

photoluminescence (PL)
photoluminescence excitation spectroscopy (PLE)
µRaman
Fourier-transform infrared elliposometry (FTIR-Ellipsometry)
UV-VIS spectral ellipsometry.

The PL measurement station uses laser wavelengths from 325 nm to 785 nm. A Ge detector is available for the infrared range and a photomultiplier can be used for the visible wavelengths. In addition, a closed-cycle cryostat is being constructed for temperatures down to 5K.

The PLE measurement station uses, in addition to the laser sources, a 1 kW xenon lamp coupled to the spectrometer. This combination of lamp and spectrometer can also be used for spectrum resolved photo-current measurements on, for example, photo-diodes and solar cells.

Stress and carrier concentration mapping with micrometer resolution can be carried out on our µRaman system. The Raman system has laser sources ranging from 457 nm to 785 nm available.

The FTIR ellipsometer can used for a number of applications ranging from traditional film thickness measurement, infrared absorption spectroscopy through to measurement of the charge carrier concentration in semiconductors and the investigation of extremely shallow p-n junctions. The system has a spatial resolution of 100 × 200 µm and can be used in combination with the UV-VIS ellipsometer.

Namlab has at its disposal a range of complementary optical methods that permit a comprehensive optical characterization from thin-film materials, e.g. absorption bands, optical centers, pump levels and energy transfer processes, to substrates, e.g. local stress, carrier concentration and photo-current measurements.