Zhaorui Song

Interfacial structures and electrical properties of HfAl2O5 gate dielectric film annealed with a Ti capping layer

HfAl2O5 gate dielectric film with an O-gettering Ti capping layer treated with rapid thermal annealing process and its interfacial structure and electrical properties were reported. X-ray reflectivity measurements and x-ray photoelectron spectroscopy suggested that the interfacial layers were composed of a 0.5nm HfAlSiO layer and a 1.5nm Six(SiO2)1−x (x<1) layer for the as-deposited film. However, for the annealed film, HfAlSiO layer was not found and the 1.5nm Six(SiO2)1−x transformed to a 1nm SiO2. The electrical measurements indicated that the equivalent oxide thickness decreased to 2.9nm, and the leakage current was only 70μA∕cm2 at the gate bias of 10MV∕cm for the annealed film.

Interfacial and Electrical Characterization of HfO2 Gate Dielectric Film with a Blocking Layer of Al2O3

HfO<inf>2</inf> gate dielectric films with a blocking layer of Al<inf>2</inf>O<inf>3</inf> inserted between HfO<inf>2</inf>/Si were treated with rapid thermal annealing process at 700°C. The interfacial structure and electrical properties are reported. X-ray photoelectron spectroscopy indicated that the interfacial layer of SiO<inf>x</inf> transformed into SiO<inf>2</inf> after the annealing treatment, and Hf-silicates and Hf-silicides were not detected. High-resolution transmission electron microscopy showed that the interfacial layer was composed of SiO<inf>2</inf> for the annealed film with a blocking layer. The electrical measurements indicated that the equivalent oxide thickness decreased to 2.5nm and the fixed charge density decreased to −4.5×10¹¹/cm² in comparison with the same thickness of HfO<inf>2</inf> films without the blocking layer. Al<inf>2</inf>O<inf>3</inf> layer could effectively prevent the diffusion of Si into HfO<inf>2</inf> film and improve the interfacial and electrical performance of HfO<inf>2</inf> film.

Characteristics of HfxSiyO films grown on Si0.8Ge0.2 layer by electron-beam evaporation

HfxSiyO gate dielectric films on strained Si0.8Ge0.2 layer were prepared by electron-beam evaporation. Their structural and electrical characteristics along with interface properties have been investigated by high-resolution transmission electron microscopy, energy dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and electrical measurements of metal-insulator-semiconductor capacitors. The dielectric film remained amorphous after annealing at 800°C. The dielectric constant is 9, a breakdown electrical field is higher than 8MV∕cm, and the leakage current is 0.1μA∕cm2 at the gate bias of 2V. Postdeposition anneal resulted in the formation of suboxidized states of Si and Ge at interface, which were responsible for the fixed oxide charges density of −5×1012cm2. No Ge-rich region was found.

Determination of sp3/sp2 ratio in amorphous-carbon thin film synthesized by reactive filtered arc deposition

Abstract The application of a silicon on insulator device in a high-power integrated circuit is limited by the self-heating effect caused by the poor thermal conductivity of the buried SiO 2 . We introduce tetrahedral amorphous-carbon thin films formed by reactive filtered arc deposition method, as an alteration. The sp 3 /sp 2 components in the thin films and the surface roughness were measured by spectroscopic ellipsometry, which is a well known non-destructive and in situ characterization method. The dielectric functions of the composite materials were calculated using the Bruggeman effective medium approximation.

Interfacial and electrical characterization of HfO 2 gate dielectric film with a blocking layer of Al 2 O 3

HfO 2 gate dielectric films with a blocking layer of Al 2 O 3 inserted between HfO 2 /Si were treated with rapid thermal annealing process at 700°C. The interfacial structure and electrical properties are reported. X-ray photoelectron spectroscopy indicated that the interfacial layer of SiO x transformed into SiO 2 after the annealing treatment, and Hf-silicates and Hf-silicides were not detected. High-resolution transmission electron microscopy showed that the interfacial layer was composed of SiO 2 for the annealed film with a blocking layer. The electrical measurements indicated that the equivalent oxide thickness decreased to 2.5nm and the fixed charge density decreased to −4.5×1011/cm2 in comparison with the same thickness of HfO 2 films without the blocking layer. Al 2 O 3 layer could effectively prevent the diffusion of Si into HfO 2 film and improve the interfacial and electrical performance of HfO 2 film.