Approximately 13 nm thick HfO2 films are grown on Si wafers by atomic layer deposition under different ozone concentrations at 280 °C using Hf[N(Et)(Me)]4 as Hf precursor.

A new model for the growth behavior of saturated HfO 2 films by atomic layer deposition (ALD) was suggested. The well-known ALD saturation of the growth rate with increasing precursor input was observed, but the full saturation required an extremely long feeding time. After the rapid increase in growth rate with increasing precursor feeding time, a pseudo-saturation region was observed where full saturation was hindered by the "screening effect" of the physisorbed precursor molecules or byproduct molecules on the chemisorbed species. The physisorbed precursor molecules screen the active adsorption sites for the following precursor. The discrete feeding method, which is the modified process recipe suggested in this study, provided improved growth behavior and electrical properties of the film.

We recommend making a skin incision on the ulnar side around the styloid process with the forearm in supination or neutral position was another method to avoid injury of DCBUN.

Hole current was directly observed in oxide semiconductors under illumination. Two stacks were fabricated, with In-Ga-Zn-O (IGZO) as the channel and SiO 2 or SiN x as the gate insulator. X-ray photoelectron spectroscopy confirmed the IGZO=SiN x interface has no hole barrier while the IGZO=SiO 2 interface has a significant one. This was used to analyze hole generation in IGZO by illuminating light at various wavelengths. As a result, a threshold wavelength, where holes start to emerge in the channel, was found to exist. Negative bias-illumination-temperature stress experiments showed that no additional threshold voltage shift exists at wavelengths longer than this threshold wavelength.Amorphous oxide semiconductors (AOSs) are promising materials that may just turn out to be the alternative for amorphous or polycrystalline silicon in the future. Their excellent electron mobility, optical clarity, guaranteed uniformity and low processing temperature are the major virtues that make the time coming of these materials so bright. 1,2 The spotlight of current research on AOSs is on thin film transistor (TFT) panels for display, where the superior mobility of AOSs (>5 cm 2 =Vs) compared to amorphous-Si (<1 cm 2 =Vs) is the primary driving force for such attention. 3 It is no exaggeration to state that almost all oxide semiconductors in current technology are ZnO-based, and among these materials, amorphous In-Ga-Zn-O (IGZO) is the most widely studied material due to its capital electrical properties and superb reproducibility. 4 Despite the massive amount of research conducted on this material, the instability of IGZO TFTs under negative bias illumination temperature stress (NBITS) still remains as a major obstacle to overcome. 5 A complete understanding of why this instability occurs in oxide semiconductors is crucial to prevent it from happening, and there have been many attempts to explain its origin, the major two arguments being the charge trapping model and the ion diffusion model. 6,7 Recently, there have been many reports supporting the charge trapping model. Kwon et al. reported the correlation between the hole barrier at the channel=gate dielectric interface and threshold voltage (V th ) shift using various gate dielectrics. 8 Similar reports by Ji et al. also support the charge trapping model under the same rationale. 9,10 Although these reports provide insight, they lack a direct correlation between observable evidence and experimental results. Therefore, in this letter, the authors attempted to directly observe the hole current of oxide semiconductors under illumination by leakage current measurements and correlate it with V th shift results.Two sets of metal oxide semiconductor capacitors (MOSCAPs) and thin film transistors (TFT) were fabricated with the bottom gate structure. A heavily doped p-type silicon (p þþ Si) wafer was used as the bottom and gate electrode. Two different gate dielectrics were used; 192 nm-thick SiO 2 thermally-grown at 1000 C and 300 nm thick SiN x , which was deposited by plasma-enha...

The negative bias illumination temperature stress instability of amorphous Hf-In-Zn-O thin film transistors with different dimensions was evaluated. The threshold voltage (Vth) shift increased in devices with shorter channel lengths but showed almost no association with the channel width. This behavior was attributed to the diffusion and drift of the photogenerated holes at the channel/dielectric interface from regions near the drain to those near the source, which were due to the simultaneous presence of gate and drain biases. The Vth near the source, which shows the largest shift and hence has the highest local value, governs the overall Vth.