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Most small molecule organic light emitting diode (SM-OLED) device structures are made in one layer using solution-based processing because the solution is usually a high dissolvent material that easily attacks the layer below it. We demonstrate a simple and reliable stamping technique for fabricating multi-solution process flexible white SM-OLEDs. The structure is anode/spin-hole injection layer/spin-emitting layer/stamping-electron transport layer/cathode. Poly(di-methyl silane) (PDMS) stamp is used for transferring electron transport layer. An intermediate ultraviolet-ozone surface treatment is introduced to temporarily modify the PDMS stamp surface. Then, the solution-based electron transport layer film can therefore be uniformly formed on top of the PDMS surface. After that the electron transport layer film on the PDMS stamp is transfer-printed onto the emitting layer with suitable heating and pressing. A solution-based processing is successfully established to efficiently fabricate flexible white SM-OLEDs. The SM-OLEDs were obtained at the current density of 20 mA/cm 2 , luminance of 1062 cd/m 2 , current efficiency of 5.57 cd/A, and Commission internationale de l'eclairage coordinate of (0.32, 0.35).

In this paper, the flexible white organic light-emitting diodes (WOLED) was fabricated on polyethylene naphthalate (PEN) with structure of ITO/EHI608 (75 nm)/HTG-1 (10 nm)/3% EB502:0.8% EY53 (5 nm)/3% EB502 (35 nm)/Alq3 (10 nm)/LiF (0.8 nm)/Al (150 nm) and was compared with glass substrate the same structure. It was seen that the performances of flexible and glass substrate are almost the same. The luminance, current efficiency, and CIE coordinates of flexible device is 6351 cd/m2, 12.7 cd/A, and (0.31, 0.38) at 50 mA/cm2, respectively. Then, an Al2O3/HfO2 film on polyethylene terephthalate (PET) was deposited using atomic layer deposition (ALD) as a thin film encapsulation layer have been described and compared, such as the characteristics of water permeability and lifetime of flexible WOLED. The results show that the PET/ALD film low value of about 0.04 g/m2d, and the PET film shows WVTR of about 3.8 g/m2/d. The lifetimes of PET/ALD and PET encapsulations are 840 min and 140 min, respectively. Simultaneous deposition of ALD film on PET film gave the lifetime of flexible WOLED is six times longer than device without ALD encapsulation.

Display Omitted Investigating PhOLEDs with different solvents and dopants concentrations.High efficiency white PhOLEDs induced by the electron transport/hole blocking material.To achieve efficient and low-cost small-molecule-based white PhOLEDs. In this study, white phosphorescent organic light-emitting diodes (PhOLEDs) have been demonstrated with small molecule by using solution processes. Spin-coating is employed as the way for deposition method. 4,4'-N,N'-dicarbazole-biphenyl (CBP) which is typical small molecule based ink is used for spin-coating method, and three phosphorescent dopants materials, Firidium(III) bis(4,6-difluoro phenyl)-pyridinato-N,C2'] picolinate (FIrpic), bis1-(phenyl) isoquinoline) iridium(III) acetyl acetonate (Ir(piq)2 (acac))], and iridium(III) tris(2-phenylpy-ridine) (Ir(ppy)3) were prepared. For spin-coating processes, various parameters properties were investigated including materials concentrations, solvents effect, and electron transporting materials to get high efficiency and white color of white PhOLED device. As a result, the precisely controlled solution processes could be a promising technology for solution process can be a good alternative of vacuum deposition technology.

A numerical procedure was performed to simplify the complicated mechanism of an epitaxial thin-film growth process. In this study, three numerical mechanism models are presented for verifying the growth rate of the gallium nitride (GaN) mechanism. The mechanism models were developed through rate of production analysis. All of the results can be compared in one schematic diagram, and the differences among these three mechanisms are pronounced at high temperatures. The simplified reaction mechanisms were then used as input for a two-dimensional computational fluid dynamics code FLUENT, enabling the accurate prediction of growth rates. Validation studies are presented for two types of laboratory-scale reactors (vertical and horizontal). A computational study including thermal and flow field was also performed to investigate the fluid dynamic in those reactors. For each study, the predictions agree acceptably well with the experimental data, indicating the reasonable accuracy of the reaction mechanisms.

Organic light-emitting diode fabrication is suffering from extremely high material wasting during deposition especially using a typical point or even line source. Moreover, the need of depositing a high number of emitters and host(s) with a precise composition control in a single layer makes traditional vapor codeposition systems nearly impossible, unless otherwise with a very low yield. To improve, we have developed a novel thin-film deposition system with a planar source loadable with any premetered solvent-mixed organic compounds, plausibly with no component number limitation. We hence demonstrate experimentally, along with a Monte Carlo simulation, in the report the feasibility of using the technique to deposit on a large area-size substrate various organic materials with a relatively high material utilization rate coupling with high film uniformity. Specifically, nonuniformity of less than ±5% and material utilization rate of greater than 70% have been obtained for the studied films.

Amorphous TiOx films and Ag layer were deposited by electron-beam evaporation on soda-lime glass at room temperature. The details regarding the structure, surface morphology, and optical properties of the as-prepared TiOx films were examined by X-ray diffraction, scanning electron microscopy, and ultra-violet (UV) -visible-near-infrared (NIR) spectrometry. The TiOx films exhibit amorphous phase with an optical band gap of 3.35 eV. The polygrains oriented along the (111) and (200) directions in the Ag films were adopted to supply carriers into the TiOx film and lower the sheet resistance of the stacked layer. The multilayer exhibited a sufficiently large Ag thickness (>15 nm), low resistance, high UV transmittance, visible transmittance, and high NIR reflection. Dependence of Ag thickness, TiOx bottom-layer, and TiOx overlayer on the optical and electrical properties of TiOx/Ag/TiOx were explored. A figure of merit (FOM) was used to find an optimal structure for a multilayer with superior conductivity and visible transparency. An FOM of 9.8 × 10−2 (Ω−1) at the visible wavelength of 550 nm for a TiOx/Ag/TiOx stacked layer with an 18-nm-thick Ag and a 20-nm-thick TiOx was achieved. The TiOx/Ag/TiOx sample annealed at 500 °C 10 min also shows a good thermal stability.

We discovered in this study the feasibility of using regular light-emitting dyes as an effective co-host, rather than a sensitizer, to markedly improve the efficiency of phosphorescent organic light emitting diodes. At 10000 cd m−2, for example, the efficacy of a yellow emitter containing device was increased from 11.7 lm W−1 to 15.4 lm W−1, an increment of 32%, as a sky-blue phosphorescent dye, bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium(III) (FIrpic), was blended into a host of 4,4′,4′′-tri(N-carbazolyl)triphenylamine (TCTA). The efficacy at 1000 cd m−2 was 26.7 lm W−1, the highest among all reported yellow OLEDs with a solution-processed emissive layer. The marked efficiency improvement may be attributed to the co-host having an electron trapping character, enabling excitons to generate on itself instead of on the guest, creating an additional efficiency-effective energy transfer route, and having a very efficient co-host to guest energy transfer. The most effective co-host may vary with the variation of the host employed, depending on the energy level pairing of the co-host and host.

We demonstrate in this report the feasibility of using organic light-emitting diode (OLED) lighting device technology to fabricate light sources with chromaticity tunable between that of dusk-hue and candle-light. The resulting color temperature is tunable easily from 1580 K to 2600 K, covering that of dusk-hue (2500 K) and candle-light (1900 K) and providing a physiologically-friendly, melatonin suppression-less emission for illumination at night, along with a respective color rendering index varying from 68 to 91 and power efficiency from 20.9 to 2.7 lm/W at 10 to 23,690 cd/m 2 . The color temperature can also be tuned from high to low sequentially, such as from 5200 K to 2360 K, covering that of cool- and warm-white light for daytime illumination, by simply varying emissive layer thickness ratio. The comparatively high color rendering index as well as the large color temperature span and easy color temperature tunability may be attributed to the employment of four blackbody radiation-complementary emitters. The emission ranges from red to sky-blue, which were dispersed into three separated emissive layers coupling with the use of a nano-layer of hole modulation material.

Light sources with lower color temperature (CT) show markedly less suppression effect on the secretion of melatonin, an oncostatic hormone. Light sources with higher color rendering index (CRI) provide better visual comfort. In this report, we demonstrate the design and fabrication of low CT, high CRI fluorescent organic light-emitting diode (OLED) with five-band emitting from a single emissive layer. The best performed device exhibits a CT of 1773 K, much lower than that of candles (1800–2000 K) or incandescent bulbs (2000–2500 K), 87 CRI, a beyond theoretical limit external quantum efficiency (EQE) 6.4%, and 11.9 lm/W at 100 cd/m 2 . One major reason for having the ultra-low CT and relative high CRI may be attributed to the significantly intensive deep red emission. The comparatively high efficacy and EQE may be attributed to the employment of a smooth stepwise energy-level structure, enabling low injection barriers and balance carrier injection.

Carbon nanotube field effect transistors (CNTFETs) have been considered as one of the potential candidates for nanoelectronics beyond Si CMOS. However, it is not easy to have high performance CNTFETs with high yield currently. In this work, we proposed a local bottom-gate (LBG) CNTFETs combined with a novel device concept and optimized process technologies. High performance of CNTFET with low subthreshold swing of 139 mV/dec, high transconductance of 1.27 μS, and high Ion/Ioff ratio of 106 can be easily obtained with Ti source/drain contact after a post annealing process. Record high yield of 74% has been demonstrated. On the basis of the proposed process, lots of high performance CNTFETs can be obtained easily for advanced study on the electrical characteristics of CNTFETs in the future.

For the first time, modification of Si doping in Hf-silicates with respect to thermal budget is investigated. Tetragonal phase of HfO2 in Hf-silicate leads to higher dielectric constant after a critical point of thermal budget. Lower critical point (lower thermal budget) is needed for Hf-silicate with a lower Si doping. The tetragonal phase induced higher dielectric constant tends to remain constant even with longer annealing time while the leakage current tends to increase. The optimum condition is a trade-off between the pro of tetragonal phase and the con of the leakage current.

Memory characteristics of the high-κ HfO2/TiO2/Al2O3 single quantum well in a p-Si/Al2O3/HfO2/TiO2/Al2O3/platinum capacitor structure have been investigated. All high-κ films have been deposited by atomic layer deposition. A significant memory window of ~1.6 V at a low gate voltage operation of 2 V, a high charge storage density of ~3.6×1012/cm2, a moderate leakage current density of 1×10-6/cm2 at a gate voltage of -2 V, and a negligible charge loss of

Nonstoichiometric hafnium oxide (HfOx) resistive-switching memory devices with low-power operation have been demonstrated. Polycrystalline HfOx (O:Hf=1.5:1) films with a thickness of 20 nm are grown on a titanium nitride (TiN) bottom electrode by commercial atomic layer deposition. Platinum (Pt) as a top electrode is used in the memory device. Voltage-induced resistance switching is repeatedly observed in the Pt/HfOx/TiN/Si memory device with resistance ratio is greater than 10. During the switching cycles, the power consumptions for high- and low-resistance states are found to be 0.25 and 0.15 mW, respectively. At 85 °C, the memory device shows stable resistance switching and superior data retention with resistance ratio is greater than 100. In addition, our memory device shows little area dependence of resistance-switching behavior. The anodic electrode containing noble metal Pt serves an important role in maintaining stable resistance switching. The resistance switching in the HfOx films is thought to be due to the defects that are generated by the applied bias. The nonstoichiometric HfOx films are responsible for the low SET and RESET currents during switching. Our study shows that the HfOx resistive-switching memory is a promising candidate for next-generation nonvolatile memory device applications.

TiO2 nanocrystals were successfully fabricated using an atomic-layer-deposition (ALD) system. A TiN/Al2O3-laminated structure was employed as a starting structure, and after appropriate annealing, TiN was oxidized and TiO2 nanocrystals were formed. Experimental results indicate that rapid thermal annealing (RTA) temperature and annealing time are very critical factors. Also, the thickness of each TiN layer in the TiN/Al2O3-laminated starting structure is critical for TiO2 nanocrystal formation. Capacitance–voltage (C–V) measurement evidenced that an optimal annealing condition exists and an optimal annealing temperature and annealing time mainly depend on the thickness of each TiN layer in the TiN/Al2O3-laminated starting structure.

A high-κ HfO2/HfAlO/HfO2 nanolaminate charge trapping layer in a p-Si/SiO2/[HfO2/HfAlO/HfO2 nanolaminate]/Al2O3/platinum memory capacitor has been investigated. High-κ HfO2, Al2O3, and HfO2/HfAlO/HfO2 nanolaminate charge trapping layers are deposited by atomic layer deposition. Well-behaved counter clockwise capacitance–voltage hysteresis characteristics are observed for all memory capacitors. A large memory window of ~10 V, a very low leakage current density of ~5×10-9 A/cm2 at a gate voltage of -5 V, a high charge trapping density of ~1.6×1013/cm2, and a low charge loss of ~20% after 10 years of retention for the HfO2/HfAlO/HfO2 nanolaminate charge trapping layer are observed as compared with those of pure HfO2 and pure Al2O3 charge trapping layers. Excellent memory characteristics of HfO2/HfAlO/HfO2 nanolaminate layers are obtained owing to the layer-by-layer charge storage. High-κ HfO2/HfAlO/HfO2 nanolaminate charge trapping layers can be used in future nanoscaled high-performance nonvolatile memory device applications.

The rougher surface and raised-hollow holes were observed in the TiN/Al2O3/HfO2/Al2O3/TiN/SiO2/Si multi-stack metal–insulator–metal (MIM) capacitor sample after 1000 °C, 60 s rapid thermal annealing (RTA) process in N2. The surface became rougher partially resulted from the nucleation of TiN layer after RTA. Experimental results also indicated that the oxygen content in the HfO2 was desorbed and the remaining Hf was crystallized. Also, the TiN and Al2O3 layers were intermixed and partially re-crystallized at this high temperature. Very clear morie fringes could be observed in the high-resolution transmission electron microscopy (HR-TEM) micrographs. Also, the energy dispersive spectroscopy (EDS) results indicated that the nitrogen in TiN was desorbed and the TiN was phase transformed to TiO2. This phenomenon might result from the TiN oxidation process during the high-temperature thermal annealing.

Thermal stability of a porous low-k film is a critical issue for application consideration in the back-end-of-line. In this study, thermal stability of the porous silicate has been investigated by changing the thermal processing temperatures. Experimental results have shown that the dielectric constant of the porous silicate still remains below 2.0 after thermal processing at 500 °C for 1 h. A series of material analysis techniques and electrical characteristics have been used to verify the physical and chemical characteristics of the porous silicate film.

A forming-free 3-nm-thick HfOx, resistive memory device is demonstrated. The percolation threshold of insulatingto-conductive transition in the ultrathin HfOx, can be lowered by using the Ti capping layer with an adequate post metal annealing. By the reaction between Ti and HfOx,, oxygen ions are depleted from the oxide, and conductive percolative paths, which consist of charged oxygen vacancies, are formed. Without any forming step, the memory can operate with stable bipolar resistance switching by initial positive or negative voltage sweep. Possible scenarios of switching mechanism for the initial state of the device with different sweep directions are proposed. This forming-free device also exhibits an on/off ratio of about ten and excellent memory performances, including high speed (~10 ns), low operation voltages ( 106 cycles), good nonvolatile property (500 min at 85 °C), and 2-b switching per cell.

The memory performance of hafnium oxide (HfOx)-based resistive memory containing a thin reactive Ti buffer layer can be greatly improved. Due to the excellent ability of Ti to absorb oxygen atoms from the HfOx film after post-metal annealing, a large amount of oxygen vacancies are left in the HfOx layer of the TiN/Ti/HfOx/TiN stacked layer. These oxygen vacancies are crucial to make a memory device with a stable bipolar resistive switching behavior. Aside from the benefits of low operation power and large on/off ratio (>100), this memory also exhibits reliable switching endurance (>106 cycles), robust resistance states (200°C), high device yield (~100%), and fast switching speed (

A novel method of fabricating HfOx-based resistive memory device with excellent nonvolatile characteristics is proposed. By using a thin AlCu layer as the reactive buffer layer into the anodic side of a capacitor-like memory cell, excellent memory performances, which include reliable programming/erasing endurance (> 105 cycles), robust data retention at high temperature, and fast operation speed (< 50 ns), have been demonstrated. The resistive memory based on AlCu/HfOx stacked layer in this letter shows promising application in the next generation of nonvolatile memory.

Candles emit sensationally-warm light with a very-low color-temperature, comparatively most suitable for use at night. In response to the need for such a human-friendly night light, we demonstrate the employment of a high number of candle light complementary organic emitters to generate mimic candle light based on organic light emitting diode (OLED). One resultant candle light-style OLED shows a very-high color rendering index, with an efficacy at least 300 times that of candles or twice that of an incandescent bulb. The device can be fabricated, for example, by using four candle light complementary emitters, namely: red, yellow, green, and sky-blue phosphorescent dyes, vacuum-deposited into two emission layers, separated by a nano-layer of carrier modulation material to maximize both the desirable very-high color rendering index and energy efficiency, while keeping the blue emission very low and red emission high to obtain the desirable low color temperature. With different layer structures, the OLEDs can also show color tunable between that of candle light and dusk-hue. Importantly, a romantic sensation giving and supposedly physiologically-friendly candle light-style emission can hence be driven by electricity in lieu of the hydrocarbon-burning and greenhouse gas releasing candles that were invented 5,000 years ago.

A mixed-deposition atomic layer deposition process produces Hf:ZnO films with uniform dopant distribution and high electrical conductivity (resistivity = 4.5 × 10(-4) W cm), optical transparency (>85% from 400-1800 nm), and moisture-barrier property (water vapor transmission rate = 6.3 × 10(-6) g m(-2) day(-1)).

Color temperature (CT) of light has great effect on human physiology and psychology, and low CT light, minimizing melatonin suppression and decreasing the risk of breast, colorectal, and prostate cancer. We demonstrates the incorporation of a blend carrier modulation interlayer (CML) between emissive layers to improve the device performance of low CT organic light emitting diodes, which exhibits an external quantum efficiency of 22.7% and 36 lm W -1 (54 cd A -1 ) with 1880 K at 100 cd m -2 , or 20.8% and 29 lm W -1 (50 cd A -1 ) with 1940 K at 1000 cd m -2 . The result shows a CT much lower than that of incandescent bulbs, which is 2500 K with 15 lmW -1 efficiency, and even as low as that of candles, which is 2000 K with 0.1 lmW -1 . The high efficiency of the proposed device may be attributed to its CML, which helps effectively distribute the entering carriers into the available recombination zones.

Light sources with low color temperature (CT) are essential for their markedly less suppression effect on the secretion of melatonin, and high power efficiency is crucial for energy-saving. To provide visual comfort, the light source should also have a reasonably high color rendering index (CRI). In this report, we demonstrate the design and fabrication of low CT and high efficiency organic light-emitting diodes. The best resultant device exhibits a CT of 1,880 K, much lower than that of incandescent bulbs (2,000–2,500 K) and even as low as that of candles, (1,800–2,000 K), a beyond theoretical limit external quantum efficiency 22.7 %, and 36.0 lm/W at 100 cd/m2. The high efficiency of the proposed device may be attributed to its interlayer, which helps effectively distribute the entering carriers into the available recombination zones.

The materials properties and resistance switching characteristics of hafnium oxide-based binary oxide were investigated for next generation memory device application. A nonstoichometric hafnium oxide (HfOx) film with a mixture structure of monoclinic and tetragonal phase and some metallic Hf-Hf bonds on TiN/Si were prepared by atomic layer chemical vapor deposition (ALCVD). Resistance random access memory devices consisting of Pt/HfOx/TiN/Si with low power operation (< 0.4 mW) and reset current (< 100 mA) were fabricated. The resistance ratio of high resistance state to low resistance state maintains 100∼1000 and after 1000 cycles of repetitively switching. A 1-nm-thick Al2O3 film in the interface between top electrode and HfOx films, the Pt/Al2O3/HfOx/TiN/Si memory devices were found that soft-error of set and reset process often occurred. Interface states in the anode side play an important role in maintaining a stable resistive switching for HfOx-based memory devices.

Organic light-emitting diodes (OLED) are an energy-efficient light source with many desirable attributes, besides being an important display of technology, but its practical application has been limited by its low air-stability. This study demonstrates air-stable flexible OLEDs by utilizing two atomic-layer-deposited (ALD) films: (1) a ZnO film as both a stable electron-injection layer (EIL) and as a gas barrier in plastics-based OLED devices, and (2) an Al2O3/ZnO (AZO) nano-laminated film for encapsulating the devices. Through analyses of the morphology and electrical/gas-permeation properties of the films, we determined that a low ALD temperature of 70 °C resulted in optimal EIL performance from the ZnO film and excellent gas-barrier properties [water vapor transmission rate (WVTR)5 × 10(-4) g m(-2) day(-1)] from both the ZnO EIL and the AZO encapsulating film. The low-temperature ALD processes eliminated thermal damage to the OLED devices, which were severe when a 90 °C encapsulation process was used, while enabling them to achieve an air-storage lifetime of10,000 h.

Characterization of the TiN coatings oxidized in air at temperatures at 600 and 700°C for 30 min was carried out by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES). TiN thin films with a Ti interlayer were prepared by hollow cathode discharge ion plating on AISI 304 stainless steel. Both XRD and TEM results show that the TiN coatings and Ti interlayer have columnar structure with (111) and (0002) preferred orientations, respectively. AFM results show the existence of pinholes on the surface of specimens due to electropolishing process of the steel substrate, and the surface roughness (Ra) changes from 3.5 nm for the as-deposited specimen to 11.6 nm after oxidation at 700°. After oxidation, the TiO2 oxide layer formed on the specimen surface was porous and retained the columnar structure as the original TiN coating. The microstructure of the Ti interlayer gradually changed from columnar to polycrystalline structure due to grain growth. The Auger elemental depth profiling indicated that interdiffusion of the Ti interlayer with steel substrate had occurred during the oxidation process.

We demonstrate herein the design and fabrication of a highly efficient yellow organic light-emitting diode (OLED) with a balanced carrier injection device architecture having a zero electron-injection-barrier host blended with a hole-injection aiding co-host. The resultant yellow OLED showed, at 1000 cd m−2 for example, an efficacy of 59 lm W−1, current efficiency of 71 cd A−1 and external quantum efficiency (EQE) of 23%, with values of 42 lm W−1, 47 cd A−1 and 15% EQE without a co-host. The co-host effect that resulted in very balanced carrier injection was also valid for other yellow OLED devices and their efficiency improvement was also very marked. With the use of a micro-lens, the device efficiency is further improved to 79 lm W−1, 96 cd A−1 and 30% EQE.

Highly efficient organic light-emitting diodes (OLEDs) are strongly demanded for both display and illumination applications. High efficiency would also help prolong the device lifespan. However, many OLEDs encounter significant roll-off problems, leading to undesired low device efficiency at high luminance, which is unfavorable to their commercial realization for lighting. Hence, OLED devices with mild or even little roll-off are highly expected. We have, nevertheless, observed some OLEDs that exhibit roll-up phenomenon, i.e., that their external quantum efficiency (EQE) or current efficiency increases as the applied voltage or brightness is increased. By taking such advantage of device architecture design, OLEDs with an approaching or even above the theoretical limit EQE are obtained at high luminance. In this report, we present how this works for a yellow OLED that exhibits a record-high power efficiency among reported fluorescent yellow OLEDs, a very-low color temperature OLED with a record-breaking efficacy based on the same color-temperature, and a green OLED. Notably, the yellow OLED exhibits an EQE that increases from 5.4 to 6.2% and current efficiency from 16.4 to 18.7 cd/A as the luminance increases from 1000 to 10,000 cd/m2. Plausible mechanisms regarding why roll-up occurs in these devices are discussed.

Low color temperature (CT) lighting sources are crucial for their low suppression of melatonin secretion, and high power efficiency is essential for energy-saving. This study demonstrates the incorporation of a blend interlayer between emissive layers to improve the device performance of low CT organic light emitting diodes. The resulting devices exhibit a CT much lower than that of incandescent bulbs, which is ∼2500 K with a ∼15 lm W−1 efficiency, and even as low as that of candles, which is ∼2000 K with ∼0.1 lm W−1. The best device fabricated shows an external quantum efficiency of 22.7% and 36 lm W−1 (54 cd A−1) with 1880 K at 100 cd m−2, or 20.8% and 29 lm W−1 (50 cd A−1) with 1940 K at 1000 cd m−2. The high efficiency of the proposed device may be attributed to its interlayer, which helps effectively distribute the entering carriers into the available recombination zones.

In this study, a charge-trapping-layer-engineered nanoscale n-channel trigate TiN nanocrystal nonvolatile memory was successfully fabricated on silicon-on-insulator (SOI) wafer. An Al2O3 high-k blocking dielectric layer and a P+ polycrystalline silicon gate electrode were used to obtain low operation voltage and suppress the back-side injection effect, respectively. TiN nanocrystals were formed by annealing TiN/Al2O3 nanolaminates deposited by an atomic layer deposition system. The memory characteristics of various samples with different TiN wetting layer thicknesses, post-deposition annealing times, and blocking oxide thicknesses were also investigated. The sample with a thicker wetting layer exhibited a much larger memory window than other samples owing to its larger nanocrystal size. Good retention with a mere 12% charge loss for up to 10 years and high endurance were also obtained. Furthermore, gate disturbance and read disturbance were measured with very small charge migrations after a 103 s stressing bias.

In this work, high-performance TiN metal nanocrystal nonvolatile memories using a p + poly-Si gate and a Al 2 O 3 blocking dielectric layer with trigate structure are fabricated on silicon-on-insulator substrate. Devices with moderate transistor performance and superior memory properties are demonstrated. A memory window as high as 5 V is achieved after Program/Ease (P/E) operation at ± 10 V for 0.1 s, with only 18 and 33% charge loss at room temperature and at 85°C after 10 years storage. Only +0.5 V window shift and almost no window narrowing after 10 5 P/E operations can be obtained. Furthermore, a device with larger nanocrystals has better P/E characteristics and superior retention performance.

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Unipolar resistive switching behaviors of Ru∕HfOx∕TiN devices with Ru as anode were investigated. Wide dispersion of switching operation parameters was observed. The conduction mechanisms in low and high resistance states of the devices were characterized to be Ohmic-like and tunneling, respectively. The band offset of the Ru∕HfOx interface was extracted from the measured tunneling current versus voltage characteristics. Instability of the band offset at the anodic interface was observed and may be responsible for the wide fluctuation of the operation voltage in the Ru∕HfOx∕TiN device at a high resistance state. The possible mechanism for these unstable characteristics of band offset at the Ru∕HfOx interface is also discussed.

Memory characteristics of TiN metal nanocrystals embedded by high-κ Al2O3 films have been investigated. The TiN (0.5 nm)/Al2O3 (1 nm) multilayers with high-κ Al2O3 film as a blocking oxide on SiO2/p-Si substrates have been deposited by Atomic Layer Deposition (ALD). After subsequent annealing treatment (>900°C), tiny TiN nanocrystals with a diameter of ∼3 nm have been formed. The size and density of TiN nanocrystals have been measured by High-Resolution Transmission Electron Microscopy (HRTEM). The densities of TiN nanocrystals are found to be ∼1.6 × 1012/cm² at 950°C for 2 min and ∼5.3 × 1012/cm² at 900° for 2 min in N2 (90%) + O2 (10%) annealing ambient. X-ray Photoelectron Spectroscopy (XPS) shows the Ti-N bonds, suggesting that the TiN nanocrystals embedded in high-κ Al2O3 films can be formed. A high programming speed of threshold voltage shift (ΔVt) ∼6.7 V @ 0.1 ms can be observed for the TiN nanocrystal memory devices. The erasing speed of ΔVt ∼6.7 V @ 20 ms is slow, due to low work function poly-Si gate electrode. The charge loss of the TiN nanocrystal memory devices is ∼14% at 20°C and ∼17% at 85°C, which is better result as compared with the best published data in the literatures. A good programming speed, endurance and retention characteristics have been observed, due to small metal nano-dot, high density and deep level charge trapping as well as strong charge confinement in the TiN nanocrystals. The memory device performance can be improved with increasing the density of TiN nanocrystals. The TiN nanocrystal flash memory devices can be useful in future nanoscale high-performance applications.

The stress in chemical-vapor-deposited silicon nitride films (∼100nm thick) is modulated by an ion implantation technique. The tensile-strained silicon nitride film is deposited on the back and front sides of a Si wafer. After implantation of P+, As+, Sb+, or BF2+ ion species, the stress of the silicon nitride film becomes compressive on the front side. It can be explained by strain relaxation of Si–N bond on the front side and highly tensile-strained Si–N bond on the back side of wafer. The compressive stress is increased with a double-implantation process because of more atomic collisions in the silicon nitride film, as well as more strain relaxation of Si–N bond on the front side of wafer. After a thermal annealing process, the compressive stress in the silicon nitride film with P+, As+, or Sb+ implantation is reduced, while compressive stress is increased for BF2+ ion implantation due to formation of the B–N bond in silicon nitride film. To justify the stress-modulated silicon nitride film by the ion ...