In semiconductor industry deposition of various thin film materials is very important for fabrication of IC devices. In this class, we offer 3 experiments for training students to learn how to fabricate different (metal, organic isolator, and functional oxide) thin films, and how to measure the properties of these thin films.
Experiment I: Organic polymer isolator thin film with a low dielectric constant
1) Coating a poly (arylethers) thin film on Si-wafer (dipping and curing);
2) Measurement of film’s thickness by optical ellipsometer; deposition of gold-electrode by mask/sputtering;
3) Measurement the change of dielectric constant and dielectric loss (or ac. resistivity) with the change of signal frequency by impedance analyzer (bridge method).
Experiment II: Stress in thin metal film on Si-wafer and oxide-wafer
1) Deposition of metal (Al) thin film on Si-wafer and quartz-wafer substrates by electron-beam method; Thickness measurement by Alpha-step;
2) Measurement of the curvature caused by the stress between the metal film and the substrates by Flexus (two-light beam reflection) method, and calculation of Young’s modulus and CTE (coefficient of thermal expansion);
3) Microstructure observation---to see hillocks formed on Al film by SEM; D.C. resistivity measured by 4 probes;
Experiment III: Ferroelectric (oxide) thin film and P-E hysteresis loop
1) Sol-gel processing to fabricate PZT (lead zirconium titanium oxide) thin film on Si-wafer (by spin-coating and sintering);
2) Identify the microstructure of the PZT film by XRD, Au-electrode sputtering and the electrode area measurement.
3) Measurement of ferroelectric P-E loop by Sowyer-Tower bridge circuit, taking photograph of the loop from oscilloscope, calculation of the polarization of the film.