AES and XPS characterization of SiNx layers

The properties of SiNx layers are largely influenced by their composition and the chemical state of the constituents. In the present study SiNx layers obtained by plasma‐enhanced and low‐pressure chemical desorption methods were characterized by AES and XPS. In the case of the most frequently applied AES characterization, the peak shape and position of the Si LVV line largely depend on the measurement parameters. In order to derive optimum conditions to minimize these effects, the energies and intensity ratios of Si LVV and N KLL peaks were examined in a wide range of AES measurement parameters: a primary electron energy of 1.0–5.0 keV and a current of 0.1–5.0 μA; sputtering conditions are: Ar+ ion energy of 0.5–3.0 keV and a current of 0.3–1.1 μA. It is clearly demonstrated that both the composition (si/N ratio) and the chemical state of silicon are affected by the applied parameters. Also, the response of the two types of layers to Ar+ ion energy showed a marked difference. As a result, optimized conditions are proposed for AES characterization. The quantitative analysis of the layers was performed by XPS. Corrected sensitivity factors for Si LVV, Si KLL and O KVV are evaluated on the basis of XPS data. It can be stated that the low‐energy Si LVV peak is more sensitive to the conditions of the measuring parameters than the high‐energy Si KLL peak, whereas the N KLL peak showed neither a significant energy shift nor a shape change.