Display Omitted Study of Gd2O3-NC memories with Al2O3/HfO2/Al2O3 (AHA) stacked tunnelling layers.Superior P/E properties achieved by Gd2O3-NC memories with optimized AHA layers.Improved retention properties obtained by Gd2O3-NC memories with AHA layers.Gd2O3-NC memories with stable VFB after a P/E cycling test of 104 times realized. Characteristics of Gd2O3-NC memories with multiple tunneling layers of Al2O3/HfO2/Al2O3 (AHA) have been investigated. It can be found that the Gd2O3-NC memory with thin bottom and thin top Al2O3 film of AHA stacked tunneling layers exhibits superior programming and erasing (P/E) properties, respectively. Compared with the memory with SiO2 tunneling layer, the retention characteristics of Gd2O3-NC memories with AHA stacked tunneling layers are significantly improved. In addition, for the memories with AHA stacked tunneling layers, the trapping energy level (Et) of shallow-trap (ST) electron loss is decreased but that of deep-trap (DT) electron loss is increased due to some shallow traps within HfO2 film and the midgap interface states at HfO2/Si interface respectively. Further, the dependence of AHA stacked layer thickness on memory characteristics can be explained by the band engineering of tunneling layer. The Gd2O3-NC memories with AHA stacked tunneling layers can sustain a stable memory window of more than 1.6V after a P/E cycling test of 104 times.

It is well-known that palladium readily absorbs hydrogen gas at room temperature. Based on this unique property of palladium, palladium oxide (PdO)-sensitive membrane in the extended gate field-effect transistor (EGFET) configurations have been evaluated as a detector for hydrogen ions in pH buffer solutions. The PdO thin film was prepared by a two-step process through reactive electron beam evaporation and subsequent thermal oxidation in an optimal O-2 flow. Our results indicate that the PdO-based EGFET sensor showed super-Nernstian sensitivity approximately 62.87 mV/pH, while exhibiting good linearity as well as good stability between pH 2 and pH 12. Our research demonstrates that PdO membrane can be used in EGFET structure without compromising sensitivity achieved by conventional methods. Furthermore, the disposable PdO sensor shows great potential for low cost biochemical detection due to its simplified fabrication and measurement system. (C) 2014 Elsevier B.V. All rights reserved.

The NH3 plasma treatment on interfacial SiO2 has been proposed to reduce the interface dipole effect of HfO2/SiO2 gate dielectric stacks. The X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV-VIS) were used to establish the band diagram of the HfO2 films. The tetragonal crystallization phase of the HfO2 films examined by X-ray diffraction (XRD) was responsible for the band-gap increase during the NH3 plasma treatment. By using the Schottky emission and Fowler-Nordheim (F-N) tunneling, the effective electron barrier height of the Al/HfO2 gate stacks can be determined. Thus, the interface dipole and Fermi-level pinning induced flat-band voltage shifts of the Al/HfO2/SiO2/p-Si structure subjected to different NH3 plasma treatment conditions were obtained. It was found that the NH3 plasma treatment for about 4 min was sufficient for achieving the zero dipole interface of the HfO2/SiO2 gate dielectric stack due to the negligible movement of the oxygen ions between the HfO2 and the nitrided oxide. (C) 2013 Elsevier B.V. All rights reserved.

In this study, Gd2O3 nanocrystal (Gd2O3-NC) memories with nanostructure tunneling layers are fabricated to examine their performance. A higher programming speed for Gd2O3-NC memories with nanostructure tunneling layers is obtained when compared with that of memories using a single tunneling layer. A longer data retention (< 15% charge loss after 104 s) is also observed. This is due to the increased physical thickness of the nanostructure tunneling layer. The activation energy of charge loss at different temperatures is estimated. The higher activation energy value (0.13 to 0.17 eV) observed at the initial charge loss stage is attributed to the thermionic emission mechanism, while the lower one (0.07 to 0.08 eV) observed at the later charge loss stage is attributed to the direct tunneling mechanism. Gd2O3-NC memories with nanostructure tunneling layers can be operated without degradation over several operation cycles. Such NC structures could potentially be used in future nonvolatile memory applications.

Dynamic charge centroid on retention characteristics of nonvolatile memories with double nanostructures (DNSs), gadolinium oxide nanocrystal (Gd2O3-NC), and hafnium oxide charge-trapping layer (HfO2-CTL) was investigated. Compared with the conventional Gd2O3-NC memory, the DNS memories exhibited superior data retention. In addition, the DNS memory with thicker HfO2-CTL presented more charge loss because the trapped charge centroid was located close to the HfO2/tunneling layer interface. The tendency of charge loss was consistent with the dynamic charge centroid at the low-flat-band-voltage shift region, indicating that the charge centroid location was important for the data retention of DNS nonvolatile memories. (C) 2012 The Japan Society of Applied Physics

Recently, nanocrystal (NC) memory such as gadolinium oxide NC (Gd2O3-NC) memory performed by the band-gap offset of a crystallized Gd2O3-NC dots surrounded by the amorphous Gd2O3 dielectrics has been proposed. The crystallization temperature was optimized and the excellent memory properties were obtained. In addition, to improve the programming/erasing (P/E) and retention characteristics of future nonvolatile memory, the BE-SONOS with SiO2/SiN/ SiO2 (ONO) tunneling layer has been proposed due to the suitable band engineering and large physical thickness. In this paper, the novel Gd2O3-NC memory with HfO2 charge trapping layer was investigated and multi-tunneling layer (Al2O3/IL-SiO2) was applied to further improve the performance. The charge storage characteristic was related to the charge trapping phenomenon of HfO2 layer.