Determination of interfacial layers in high-k nanomaterials by ADXPS measurements

The interfacial layers of high dielectric constant (high - k) nanolaminate films are here explored. Problems concerning ALD nanolaminate layers deals mainly with lack of accurate methods to determine in depth profile of few nm thick stacks. Angle Dependent XPS (ADXPS) is proposed as method suitable in layer profiling. Studied stacks containing industrial grown ZrO₂/HfO₂ films( d~3 nm) were processed with various parameters resulting in both, layer by layer and homogenous depositions. For those and pure HfOx samples exsitu XPS, with angle dependent variation of probing depth, measurements were covered. By comparing obtained intensity ratios for different angles with computational developed stack model it was found that no simple layer by layer but some intermixing growth occurred including interaction with substrate and diffusion of silicon.