Properties, process control, and characterization of PECVD silicon nitrides for compound semiconductor devices

We demonstrate the use of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and spectroscopic ellipsometry (SE) to determine thickness of silicon nitrides for compound semiconductor devices, describing in detail the accuracy and convenience of each technique. In addition to thickness, nitride composition is another process parameter that needs to be controlled. Therefore, we also discuss using UV Raman spectroscopy, Rutherford backscattering spectroscopy, and spectroscopic ellipsometry to measure composition. Finally, we discuss the correlation between electrical parameters (capacitance and breakdown voltage) and the stoichiometry of the silicon nitride used as a dielectric in a metal-insulator-metal capacitor.