SEMATECH and NIST Collaborate on Chemical Analysis of Advanced Gate Dielectrics
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Figure 1. Si 1s spectra from 3nm HfO2/ 2nm SiO2 sample recorded with variable kinetic energy XPS illustrates depth profiling sensitivity and an interface effect near HfO2.
Nitrogen incorporation in thin HfO
2/SiO
2 film systems representative of high-k gate dielectric layers in advanced metal-oxide semiconductor field-effect transistors (MOSFETs) has been investigated by synchrotron x-ray photoelectron spectroscopy to elucidate variations in chemical composition between samples annealed in NH
3 and N
2 ambient as a function of temperature. In addition, depth profiling of core-level binding energy spectra has been obtained by variable kinetic energy x-ray photoelectron spectroscopy (VKE-XPS) with tunable photon energy. An HfO
2/SiO
2 “interface effect” has been detected in the Si 1s spectra characterized by a shift of the Si
4+ feature to lower binding energy with no corresponding chemical state change observed in the Hf 4f spectra acquired over a broad range of electron take-off angles.
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