Optimization of optoacoustic cell for depth profiling studies of semiconductor surfaces

The authors present a simple theory to explain how optoacoustic depth profiling studies of an opaque solid surface dimension and coupling gas. An experimental cell suitable for such studies for a Si surface is constructed and experimental results taken at large and small gas column lengths lg (compared to gas thermal diffusion length) supported theoretical predictions. At large (small) lg, signal strength for He is about 3.2 (1.1) times that for N2 as the coupling gas used, in agreement with theory.