Sputtered depth scales of multi-layered samples with in situ laser interferometry: arsenic diffusion in Si/SiGe layers

Abstract Diffused arsenic profiles in multi-layer Si–SiGe structures are used to characterize an in situ depth measurement system. The laser interferometer method shows problems with the depth scale both at the sample surface and interfaces for these layered materials, and does not improve the depth scale accuracy over crater depth measurements after analysis. Initial negative depth values indicate a volume expansion of the sample from the primary species implantation. Improved interpretation of the laser interaction with the sample will be needed to implement an interferometer for accurate depth scales on layered samples.