The effect of low fluence single pulse laser annealing on a pulsed laser deposited high-k dielectric, Lu 2 O 3 is reported. With low fluence laser irradiation, high "k" of 45 is achieved with an equivalent oxide thickness of 0.39 nm, without taking into account the quantum mechanical tunneling effect. High-resolution transmission electron microscopy micrograph revealed well-ordered epitaxial-like interfacial layer. High-resolution Rutherford backscattering confirmed the presence of Lu-based silicate layer at the interface. It was proposed that the high dielectric constant was caused by the increased ionic polarizability in the film, thereby increasing the ionic contribution of the dielectric constant.
Effects of Ti alloying during laser-induced Ni silicide formation is studied. Unique triple layer microstructures were found with the presence of supercell in the NiSi2 grains formed at the interface. This supercell formation was caused by a local ordering of Ni and Si atoms that favor lower free energy during rapid solidification. Ti rapidly segregates from the alloy melt and forms a protective TiOx overlayer on the surface during solidification. Melt front progressing towards the Ni-rich region leads to quenching of an amorphous layer sandwiched between NiSi2 grains and the TiOx overlayer.
We have successfully developed a novel method to fabricate the memory structure of Ge nanocrystals embedded in amorphous Lu2O3 high-k dielectric using pulsed laser ablation. The mean size and aerial density of the Ge nanocrystals are estimated to be about 9 nm and 7 × 10 11 cm −2 , respectively. Good performances in terms of large memory window and long data retention were observed. Our preparation method is simple, fast and economical.
A novel method to fabricate the memory structure of LaAlO 3 nanocrystals embedded in amorphous Lu 2 O 3 high-k dielectric by the pulsed laser deposition method using a rotating target was successfully developed. The average mean size and aerial density of the LaAlO 3 nanocrystals are estimated to be about 6 nm and 1.1 ϫ 10 12 cm −2 , respectively. Superior performances in terms of a large memory window, long data retention, and robust endurance were observed.Significant attention has been shifted to semiconductor nanoparticles embedded in the silicon dioxide ͑SiO 2 ͒ of a metal-insulatorsemiconductor ͑MOS͒ device for future high speed and low power consuming logic and memory devices in the recent years. 1,2 Conventional floating gate ͑FG͒ devices have their limitations; the most prominent one is the limited potential for continued scaling of the device structure. This is due to the stringent requirement placed on the tunnel oxide layer. There is often a trade-off between speed and reliability in a conventional flash gate to allow an acceptable charge transfer rate to and from the floating gate, with satisfactory charge retention. 3 Therefore, in order to overcome the scaling limits of FG devices, floating gates incorporating isolated nanocystals have been introduced. The use of nanocrystal nonvolatile memory devices would allow thinner injection oxides, thereby allowing better endurance, lower operating voltages, and faster write/erase speeds. 2,4 Moreover, the presence of the isolated dots reduces the problems of charge loss encountered in conventional flash memories. The use of high-k dielectric in place of the conventional SiO 2 -based dielectric means that programming efficiency, and data retention 5,6 in the nanocrystal nonvolatile memories can be significantly improved. Presently, work on the integration of high-k dielectric materials with nanodots is limited.Lanthanide oxides are potential high-k alternative candidates for gate insulators because of their desirable characteristics such as large bandgap, high relative dielectric constant, and low leakage current. 7-10 Some of the lanthanide oxides show good properties without the preformed interfacial layer, and are regarded as promising candidates for next generation high-k dielectrics. 11 Among the lanthanide oxides, Lu 2 O 3 has a moderately high dielectric constant around 12, 12,13 and is predicted to be thermodynamically stable on Si. 14,15 It has also been shown that single-crystalline LaAlO 3 is stable in contact with silicon under standard metal oxide semiconductor ͑MOS͒ device processing conditions of 1026°C for 20 s. 16 This makes LaAlO 3 a promising candidate material to be integrated in MOS devices.An advantage of the pulsed laser deposition ͑PLD͒ method is the possibility for stoichiometric transfer of the ablated material from the target to the film. In this letter, we report a method to produce LaAlO 3 nanocrystals in amorphous Lu 2 O 3 high-k dielectric matrices using a variation of the pulsed-laser deposition method with a rotating target. ...
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