We demonstrate significantly improved thermal stability of the amorphous phase for hafnium-based gate dielectrics through the controlled addition of Al2O3. The (HfO2)x(Al2O3)1−x films, deposited using atomic layer deposition, exhibit excellent control over a wide range of composition by a suitable choice of the ratio between the Al and Hf precursor pulses. By this method, extremely predictable hafnium aluminate compositions are obtained, with Hf cation fractions ranging from 20% up to 100%, as measured by medium energy ion scattering. Using x-ray diffraction, we show that (HfO2)x(Al2O3)1−x films with Hf:Al∼3:1 (25% Al) remain amorphous up to 900 °C, while films with Hf:Al∼1:3 (75% Al) remain amorphous after a 1050 °C spike anneal.

We report the effects of annealing on the morphology and crystallization kinetics for the high-gate dielectric replacement candidate hafnium oxide (HfO 2 ). HfO 2 films were grown by atomic layer deposition ͑ALD͒ on thermal and chemical SiO 2 underlayers. High-sensitivity x-ray diffractometry shows that the as-deposited ALD HfO 2 films on thermal oxide are polycrystalline, containing both monoclinic and either tetragonal or orthorhombic phases with an average grain size of ϳ8.0 nm. Transmission electron microscopy shows a columnar grain structure. The monoclinic phase predominates as the annealing temperature and time increase, with the grain size reaching ϳ11.0 nm after annealing at 900°C for 24 h. The crystallized fraction of the film has a strong dependence on annealing temperature but not annealing time, indicating thermally activated grain growth. As-deposited ALD HfO 2 films on chemical oxide underlayers are amorphous, but show strong signatures of ordering at a subnanometer level in Z-contrast scanning transmission electron microscopy and fluctuation electron microscopy. These films show the same crystallization kinetics as the films on thermal oxide upon annealing.

Ultrashallow p+/n junctions formed by B+-ion implantation and annealed by spike rapid thermal annealing (RTA) or laser annealing were studied. The effect of the preamorphizing depth on the redistribution of boron atoms after annealing has also been investigated. Our results show that for ultrashallow junctions formed by ultra-low-energy ion implantation and spike RTA, the depth of the preamorphizing implant has very little impact on the junction depth. By optimizing the laser fluence and preamorphization depth, a highly activated, ultrashallow, and abrupt junction can be obtained using a 248 nm excimer laser. The secondary-ion-mass spectrometry results clearly indicate that a step-like profile with a junction depth of 370 Å (for a B+ implant at 1 keV) can be formed with a single-pulse laser irradiation at 0.5 J/cm2.

The stumbling block of employing Raman imaging in nanoscience and nanotechnology is the diffraction-limited spatial resolution. Several approaches have been employed to improve the spatial resolution, among which aperture and apertureless near-field Raman techniques are the most frequently used. In this letter, we report a new approach in doing near-field Raman imaging with spatial resolution of about 80 nm, by trapping and scanning a polystyrene microsphere over the sample surface in water. We have used this technique to resolve PMOS transistors with SiGe source drain stressors with poly-Si gates, as well as gold nanopatterns with excellent reproducibility.

In this article we report the role of excess interstitials in the end-of-range region in transient enhanced diffusion of boron during annealing of laser-processed samples. The results show that although the amorphous layer in preamorphized silicon can be completely annealed by laser irradiation, the end-of-range damages were not sufficiently annealed. The end-of-range region contains a supersaturation of interstitial defects that enhance the diffusion of boron during a post-laser processing anneal. It is found that the transient enhanced diffusion is significantly suppressed when the melt depth is extended beyond the amorphous layer such that the interstitial dose in the region adjacent to the laser-melted layer is minimized. In this way, the abruptness of laser-processed ultrashallow junctions can be maintained upon further annealing at moderately high temperatures. Cross-sectional transmission electron microscopy shows that a virtually defect-free regrown layer is obtained by overmelting beyond the amorphous layer into the substrate.