High-resolution X-ray microdiffraction from a locally strained SOI with a width of 150 nm

Abstract

150-nm-wide region in a locally strained silicon on insulator (SOI) was studied using high-resolution X-ray microdiffraction technique. Synchrotron radiation X-rays with energies of 10 keV were focused on the sample by a zone plate. The focused beam size was approximately 0.8 × 0.4 μm2. The sample was a model of a gate of metal-oxide semiconductor field-effect-transistors (MOSFETs); a 30-nm-thick SOI plate with an 80-nm-thick silicon nitride capping film with tensile inner stress. The capping film was removed in a stripe pattern by etching with a width of 150 nm. The width of the gap where the film is removed corresponds to the gate length of MOSFETs. Using thin SOI as a sample, we could observe only thin surface area even by X-ray diffraction that has deep penetration depth. Reciprocal space maps (RSMs) of symmetrical SOI 004 were measured around the 150-nm-gap of the film. RSMs showed that the SOI lattice was tilted along the stripe pattern up-to 0.1 deg at both sides of the gap. The tilting spreads more than 1 μm distant from the center of the gap.