Semiconductor characterization techniques

The purpose of this article is to summarize the methods used to experimentally characterize a semiconductor material or device (PN junction, Schottky diode, etc.). Some examples of semiconductor quantities that could be characterized include depletion width, carrier concentration, optical generation and recombination rate, carrier lifetimes, defect concentration, trap states, etc.

These quantities fall into three categories when it comes to characterization methods: 1) Electrical Characterization 2) Optical Characterization 3) Physical/Chemical Characterization

Electrical Characterization Techniques

Electrical Characterization can be used to determine resistivity, carrier concentration, mobility, contact resistance, barrier height, depletion width, oxide charge, interface states, carrier lifetimes, and deep level impurities.

Two-Point Probe, Four-Point Probe, Differential Hall Effect, Capacitance-Voltage Profiling, DLTS, Electron beam-induced current, and DLCP.

Optical Characterization

Optical Characterization may include microscopy, ellipsometry, photoluminescence, transmission spectroscopy, absorption spectroscopy, raman spectroscopy, reflectance modulation, cathodoluminescence, to name a few.

Physical/Chemical Characterization

Electron Beam Techniques - SEM, TEM, AES, EMP, EELS

Ion Beam Techniques - Sputtering, SIMS, RBS

X-Ray Techniques - XRF, XPS, XRD, X-ray topography Neutron Activation Analysis (NAA) Chemical Etching

Future Characterization Methods

Many of these techniques have been perfected for silicon making it the most studied semiconductor material. This is a result of silicon's affordability and prominent use in computing. As other fields such as power electronics, LED devices, photovoltaics, etc. begin to come of age, characterization of a variety of alternative materials will continue to increase (including organics). Many of the existing characterization methods will need to be adapted to accommodate the peculiarities of these new materials.

References

Schroder, Dieter K. Semiconductor Material and Device Characterization. 3rd Ed. John Wiley and Sons, Inc. Hoboken, New Jersey, 2006.

McGuire, Gary E. Characterization of Semiconductor Materials: Principles and Methods. Vol 1. Noyes Publications, Park Ridge, New Jersey, 1989.