Secondary ion mass spectrometry (SIMS) is an excellent technique to characterize III nitride materials and devices (dopants, impurities, and composition). Using empirical standards, the ion yield trends are derived for III nitride matrices to enable quantitative and high precision characterization of both major and impurity elements. The technique can be employed to investigate the control of purity and doping, determine growth rate and composition, as well as reveal the structure of finished optoelectronic and electronic devices. SIMS is thus a powerful tool for failure analysis, reverse engineering, and concurrent engineering.