Effect of Oxygen Pressure on the Electrical Properties of $hbox{Bi}_{5} hbox{Nb}_{3}hbox{O}_{15}$ Films Grown by RF Magnetron Sputtering

$hbox{Bi}_{5}hbox{Nb}_{3}hbox{O}_{15} (hbox{B}_{5}hbox{N}_{3})$ films grown under a low oxygen partial pressure (OP) of 1.7 mtorr showed a high leakage current density of 0.1 $hbox{A/cm}^{2}$ at 1.0 MV/cm. However, the leakage current density decreased with increasing OP to a minimum of $hbox{5.8} times hbox{10}^{-9} hbox{A/cm}^{2}$ for the film grown under 5.1 mtorr due to the decreased number of oxygen vacancies. This film also showed an improved breakdown field of 2.2 MV/cm and a large capacitance density of 24.9 $hbox{fF}/muhbox{m}^{2}$. The electrical properties of the film, however, deteriorated with a further increase in OP, which is probably due to the formation of oxygen interstitial ions. Therefore, superior electrical properties for the $ hbox{B}_{5}hbox{N}_{3}$ film can be obtained by careful control of OP.      

Bandgap-Engineered Ga-Rich GaZnO Thin Films for UV Transparent Electronics

Ga-rich GaZnO thin films were prepared by metal–organic chemical vapor deposition. The optical bandgap of GaZnO films can be engineered from 3.3 to 4.9 eV by varying the Ga content. The film is amorphortized and the resistivity increases with an increase of Ga content. The Ga-rich GaZnO alloy with lower resistivity is investigated as a UV transparent conductor, while the semi-insulating Ga-rich GaZnO film with high transparency at 280–900 nm is employed as the channel layer to fabricate deep UV transparent thin-film transistor. The transistor shows a typical n-channel field-effect characteristic with a current on/off ratio of $hbox{10}^{4}$–$ hbox{10}^{5}$, a threshold voltage of $sim$42 V, a saturated field-effect mobility of $sim!hbox{0.06} hbox{cm}^{2} cdot hbox{V}^{-1} cdot hbox{s}^{-1}$, and a subthreshold swing of $ sim!hbox{7.7} hbox{V} cdot hbox{decade}^{-1}$.      

Electrical Properties of $hbox{Bi}_{5}hbox{Nb}_{3} hbox{O}_{15}$ Thin Film Grown on $hbox{TiN}/hbox{SiO}_{2}/ hbox{Si}$ at Room Temperature for Metal–Insulator–Metal Capacitors

Buckling was observed in $hbox{Bi}_{5}hbox{Nb}_{3}hbox{O}_{15}$ (BiNbO) films grown on $hbox{TiN}/hbox{SiO}_{2}/hbox{Si}$ at 300 $^{circ}hbox{C}$ but not in films grown at room temperature and annealed at 350 $^{circ}hbox{C}$. The 45-nm-thick films showed a high capacitance density and a low dissipation factor of 8.81 $hbox{fF}/muhbox{m}^{2}$ and 0.97% at 100 kHz, respectively, with a low leakage current density of 3.46 $hbox{nA}/hbox{cm}^{2}$ at 2 V. The quadratic and linear voltage coefficients of capacitance of this film were 846 $hbox{ppm}/hbox{V}^{2}$ and 137 ppm/V, respectively, with a low temperature coefficient of capacitance of 226 $hbox{ppm}/^{circ}hbox{C}$ at 100 kHz. This suggests that a BiNbO film grown on a $hbox{TiN}/ hbox{SiO}_{2}/hbox{Si}$ substrate is a good candidate material for high-performance metal–insulator–metal capacitors.      

Corrections to “Growth of Lanthanum Manganate Buffer Layers for Coated Conductors via a Metal–Organic Decomposition Process”

In our prior paper, we reported forming (110)-oriented LaMnO$_3$ on a biaxially textured Ni-3at%W substrate. Chemical analysis of these films subsequent to publishing the paper showed only La and O—there was no Mn present in the film. The film was actually (400)-oriented La$_2$O$_3$ with the cubic bixbyite structure. Subsequent studies also showed that MnO film is not stable on Ni and Ni–W substrate surfaces at 1100 $^{circ}$C and $hbox{P}_{{rm O}2} = 10^{-16}$ atm where bulk MnO is stable.      

Novel Nano-Scale Conductive Films With Enhanced Electrical Performance and Reliability for High Performance Fine Pitch Interconnect

In this paper, a novel nano-scale conductive film which combines the advantages of both traditional anisotropic conductive adhesives/films (ACAs/ACFs) and nonconductive adhesives/films (NCAs/NCFs) is introduced for next generation high-performance ultra-fine pitch packaging applications. This novel interconnect film possesses the properties of electrical conduction along the $z$ direction with relatively low bonding pressure (ACF-like) and the ultra-fine pitch $({≪ 30}~ mu {rm m})$ capability (NCF-like). The nano-scale conductive film also allows a lower bonding pressure than NCF to achieve a much lower joint resistance (over two orders of magnitude lower than typical ACF joints) and higher current carrying capability. With low temperature sintering of nano-silver fillers, the joint resistance of the nano-scale conductive film was as low as $10 ^{-5}~{rm Ohm}$. The reliability of the nano-scale conductive film after high temperature and humidity test (85$^{circ}{rm C}$/85% RH) was also improved compared to the NCF joints. The insertion loss of nano-scale conductive film joints up to 10 GHz was almost the same as that of the standard ACF or NCF joints, suggesting that the nano-scale conductive film is suitable for reliable high-frequency adhesive joints in microelectronics packaging.      

Soft Glass Equiangular Spiral Photonic Crystal Fiber for Supercontinuum Generation

An equiangular spiral photonic crystal fiber (ES-PCF) design in soft glass is presented that has high nonlinearity ( $gamma>5250 hbox{W}^{-1}cdothbox{km}^{-1}$ at 1064 nm and $gamma>2150 hbox{W}^{-1}cdothbox{km}^{-1}$ at 1550 nm) with a low and flat dispersion (${D}sim {hbox {0.8}} hbox{ps/km}cdothbox{nm}$ and dispersion slope $sim-0.7 hbox{ps/km}cdothbox{nm}^{2}$ at 1060 nm). The design inspired by nature is characterized by a full-vectorial finite element method. The ES-PCF presented improves over the mode confinement of triangular core designs and dispersion control of conventional hexagonal PCF, combining the advantages of both designs; it can be an excellent candidate for generating supercontinuum pumped at 1.06 $mu{hbox {m}}$.      

Effect of Gate Dopant Diffusion on Leakage Current in n+Poly-Si/HfO2 and Examination of Leakage Paths by Conducting Atomic Force Microscopy

The effect of gate dopant diffusion on leakage current has been investigated in $hbox{n}^{+}hbox{poly-Si}/hbox{HfO}_{2}$ capacitors. The $hbox{HfO}_{2}$ films with low gate doping concentration exhibited very low leakage currents, whereas the films with heavy gate doping concentration showed excessive leakage currents. Conducting atomic force microscopy was applied to examine the current images of the $hbox{HfO}_{2}$ films showing excessive leakage currents, and evident leakage paths with annular shape were observed. The leakage paths observed in the $hbox{HfO}_{2}$ films with heavy doping poly-Si gate may be related to the diffusion of the excessive dopant from the $hbox{n}^{+}$ poly-Si gate into the $hbox{HfO}_{2}$ , particularly through the grain boundaries in the films. This may significantly increase the leakage currents in the $hbox{n}^{+}hbox{poly-Si}/hbox{HfO}_{2}$ devices.      

Thermoelectric Microconverter for Energy Harvesting Systems

This paper presents a solution for energy microgeneration through energy harvesting by taking advantage of temperature differences that are converted into electrical energy using the Seebeck effect. A thermoelectric microconverter for energy scavenging systems that can supply low-power electronics was fabricated using thin films of bismuth and antimony tellurides. Thin films of n-type bismuth $(hbox{Bi}_{2} hbox{Te}_{3})$ and p-type antimony $(hbox{Sb}_{2} hbox{Te}_{3})$ tellurides were obtained by thermal coevaporation with thermoelectric figures of merit $(ZT)$ at room temperature of 0.84 and 0.5 and power factors $(PF times 10^{-3} [hbox{W} cdot hbox{K}^{-1}cdot hbox{m}^{-2}])$ of 4.87 and 2.81, respectively. The films were patterned by photolithography and wet-etching techniques. The goal for this thermoelectric microconverter is to supply individual electroencephalogram (EEG) modules composed by an electrode, processing electronics, and an antenna, where the power consumption ranges from hundredths of microwatts to a few milliwatts. Moreover, these wireless EEG modules allow patients to maintain their mobility while simultaneously having their electrical brain activity monitored.      

Electrical Properties of Amorphous $hbox{Bi}_{5} hbox{Nb}_{3}hbox{O}_{15}$ Thin Film for RF MIM Capacitors

Amorphous $hbox{Bi}_{5}hbox{Nb}_{3}hbox{O}_{15}(hbox{B}_{5} hbox{N}_{3})$ film grown at 300 $^{circ}hbox{C}$ showed a high-$k$ value of 71 at 100 kHz, and similar $k$ value was observed at 0.5–5.0 GHz. The 80-nm-thick film exhibited a high capacitance density of 7.8 fF/$muhbox{m}^{2}$ and a low dissipation factor of 0.95% at 100 kHz with a low leakage-current density of 1.23 nA/ $hbox{cm}^{2}$ at 1 V. The quadratic and linear voltage coefficient of capacitances of the $hbox{B}_{5}hbox{N}_{3}$ film were 438 ppm/$hbox{V}^{2}$ and 456 ppm/V, respectively, with a low temperature coefficient of capacitance of 309 ppm/$^{circ}hbox{C}$ at 100 kHz. These results confirmed the potential of the amorphous $hbox{B}_{5}hbox{N}_{3}$ film as a good candidate material for a high-performance metal–insulator–metal capacitors.      

Pentacene-Based Low-Voltage Strain Sensors With PVP/$ hbox{Ta}_{2}hbox{O}_{5}$ Hybrid Gate Dielectrics

Field-controllable pentacene-semiconductor-based strain sensors were fabricated with hybrid gate dielectrics using polyvinyl phenol (PVP) and high-$k$ inorganic tantalum pentoxide $(hbox{Ta}_{2}hbox{O}_{5})$ onto polyethylene naphthalate films. The $hbox{Ta}_{2}hbox{O}_{5}$ gate-dielectric layer combined with a thin PVP layer to form very smooth and hydrophobic surfaces turns out to improve the molecular structures of pentacene films significantly. The PVP– $hbox{Ta}_{2}hbox{O}_{5}$ hybrid-gate-dielectric films exhibit a high dielectric constant of 19.27 and a leakage-current density of as low as 100 $hbox{nA/cm}^{2}$ . The sensors employing a thin-film-transistor-like Wheatstone bridge configuration able to operate at reduced voltage ($sim$4 V) show good device characteristics with a field-effect mobility of 1.89 $hbox{cm}^{2}/hbox{V} cdot hbox{s}$ and a threshold voltage of $-$0.5 V. The strain sensor characterized with bending at 45$^{circ}$ with respect to the bridge bias direction with different bending radii of 50-, 40-, 30-, 20-, and 8-mm displays output signals improved in linearity in a low range of operating voltages.      

Crystallization of Double-Layered Silicon Thin Films by Solid Green Laser Annealing for High-Performance Thin-Film Transistors

We report a new laser crystallization method employing double-layered amorphous-Si ( $a$-Si) thin films for solid green laser annealing (GLA) crystallization that is called GLA double-layered x'tallization (GLADLAX). Crystallization of the upper and lower $a$-Si layers of the double-layered substrate at a single laser scanning was achieved, with the upper $a$-Si becoming poly-Si with very large crystal grains and the lower $a$-Si layer becoming microcrystalline Si. Thin-film transistors using the upper layer of poly-Si that is crystallized by the method as their active channels had excellent switching performance, with their mobility exceeding 350 $hbox{cm}^{2}/hbox{V} cdot hbox{s}$, demonstrating promising applicability of GLADLAX to thin-film electronics.      

New n-Type $hbox{TiO}_{2}$ Transparent Active Channel TFTs Fabricated With a Solution Process

New metal–oxide thin-film transistors (MOxTFTs) with a solution-processed $hbox{TiO}_{2}$ transparent active channel are fabricated with a novel doping process that consists of a deposition of an ultrathin Ti layer on $hbox{TiO}_{2}$ films and a brief rapid thermal annealing. Contrary to an as-prepared device which does not show any appreciable TFT actions, devices with the proposed process exhibit a clear n-type TFT behavior with a saturation mobility of 0.12 $hbox{cm}^{2}cdothbox{V}^{-1}cdothbox{s}^{-1}$ and a threshold voltage of 11 V. A solution processibility and a low-cost manufacturability of $hbox{TiO}_{2}$ make the presented TFTs potentially attractive for cost-sensitive applications.      

A Low Power, Scalable, DAC Architecture for Liquid Crystal Display Drivers

The proliferation of portable electronic products such as cellular telephones and personal digital assistants has created a high demand for small format liquid crystal displays (LCD) with increasing bit resolution. The electronic drivers for these display applications must adhere to stringent power and area budgets. This paper describes a low-power, area efficient, scalable, digital-analog conversion (DAC) integrated circuit architecture optimized for driving small format LCDs. A 12 channel, 9-bit DAC driver based on this architecture, implemented in 0.5 $mu$ m CMOS technology and suitable for 1/4 VGA resolution displays, exhibited a 2 MSPS conversion rate, 252 $muhbox{W}$ power dissipation per channel using a 5 V supply, and a per DAC die area of 0.042 $hbox{mm}^{2}$. This performance sets a new standard for DAC display drivers in joules per bit areal density at less than 0.58 pJ per bit per $hbox{mm}^{2}$ .      

Correlation of Charge Buildup and Stress-Induced Leakage Current in Cerium Oxide Films Grown on Ge (100) Substrates

High-$kappa$ films are currently deposited on Ge substrates to compensate the mobility loss, as Ge offers higher mobility compared with that of silicon. This paper deals with the reliability characteristics of cerium oxide films grown by molecular beam deposition on n-type Ge (100) substrates. MOS capacitors with Pt gate electrodes were subjected to constant voltage stress conditions at accumulation. The correlation of the charge-trapping characteristics and the stress-induced leakage current (SILC) to the applied field is observed and analyzed. The results suggest that one major problem for the potential use of rare earth oxides in future MOS technology is the existence of relaxation effects. The cross-sectional value of the bulk oxide traps is on the order of $hbox{10}^{-18} hbox{cm}^{2}$ , thus indicating neutral defects. Direct comparison to reported results on high- $kappa/hbox{Si}$ and $ hbox{SiO}_{2}/hbox{Si}$ structures shows that SILC properties are related to the quality of the dielectric layers; the semiconductor substrate is immaterial.      

Improved Electrical Characteristics of Amorphous Oxide TFTs Based on $hbox{TiO}_{x}$ Channel Layer Grown by Low-Temperature MOCVD

We report on the fabrication of n-type thin-film transistors (TFTs) based on $hbox{TiO}_{x}$ channels grown by the metal–organic chemical vapor deposition method with the chamber temperature of 250 $^{circ}hbox{C}$. These TFTs exhibit ideal characteristics with the flat saturation, low subthreshold swing, and narrow hysteresis window, all of which are a clear improvement from our previous work based on $ hbox{TiO}_{2}$ nanoparticles. The $hbox{TiO}_{x}$ film in this letter is identified to be in the amorphous phase from X-ray diffraction analysis, and its carrier density is estimated to be $hbox{2.6} times hbox{10}^{17} hbox{cm}^{-3}$ from the transmission line model and analysis of TFT on-resistance measured at various gate biases and channel lengths.      

Microcrystalline-Silicon Transistors and CMOS Inverters Fabricated Near the Transition to Amorphous-Growth Regime

Thin-film transistors (TFTs) are core elements of novel display media for large-area electronic applications. Microcrystalline-silicon TFTs prepared at low temperatures $(hbox{150} ^{circ} hbox{C} {-} hbox{200} ^{circ}hbox{C})$ have recently gained much attention as potential elements for such applications due to their high charge carrier mobilities exceeding 10 $hbox{cm}^{2}/hbox{V} cdot hbox{s}$. Understanding the relationship between structural properties and charge transport is the key in realizing transistors with high charge carrier mobility at low temperatures. In this paper, we investigated the correlation between the structural properties of microcrystalline silicon and the performance of high-mobility microcrystalline-silicon TFTs. Transistors with high electron and hole charge carrier mobilities exceeding 50 and 12 $hbox{cm}^{2}/hbox{V} cdot hbox{s}$, respectively, were realized near the transition to the amorphous-growth regime. The results reveal that electronic defects at the grain boundaries of silicon crystallites are passivated by the amorphous phase. The results contradict the commonly believed assumption that the highest charge charier mobility can only be achieved for films with high or very high crystalline-silicon volume fraction. The crystalline volume fraction of the material will be correlated to the device parameters of transistors. Furthermore, the first results of microcrystalline-silicon-TFT-based complementary-metal–oxide–semiconductor inverters with high voltage gains exceeding 22 will be presented.      

Schottky Barrier N-Type Thin Film Transistors With Polycrystalline Silicon Channel and Er-Silicided Metallic Junctions

N-type Schottky barrier thin film transistors (SB-TFTs) with polycrystalline silicon channel and metallic junctions were fabricated by using Er silicidation, and electrical structural properties were compared to conventional TFTs with phosphorous-doped source/drain regions. The performances of SB-TFTs are better than that of the conventional TFTs. A forming gas annealing process leads to a great improvement in the characteristics of both devices. In particular, excellent electrical characteristics were obtained from the forming gas annealed SB-TFTs: the subthreshold swing of 180 mV/dec, the drive current of $hbox{1.47} times hbox{10}^{-5} hbox{A}$, and the on/off current ratio of $ hbox{5} times hbox{10}^{6}$.      

Schottky Barrier Height Modulation of Nickel–Dysprosium-Alloy Germanosilicide Contacts for Strained P-FinFETs

This letter reports on the fabrication and hole Schottky barrier $(Phi_{ rm B}^{rm p})$ modulation of a novel nickel (Ni)–dysprosium (Dy)-alloy germanosilicide (NiDySiGe) on silicon–germanium (SiGe). Aluminum (Al) implant is utilized to lower the $Phi_{rm B}^{rm p}$ of NiDySiGe from $sim$0.5 to $sim$ 0.12 eV, with a correspondingly increasing Al dose in the range of $ hbox{0}$–$hbox{2}timeshbox{10}^{15} hbox{atoms}/ hbox{cm}^{2}$. When integrated as the contact silicide in p-FinFETs (with SiGe source/drain), NiDySiGe with an Al implant dose of $hbox{2}timeshbox{10}^{14} hbox{atoms}/ hbox{cm}^{2}$ leads to 32% enhancement in $I_{rm DSAT}$ over p-FinFETs with conventional NiSiGe contacts. Ni–Dy-alloy silicide is a promising single silicide solution for series-resistance reduction in CMOS FinFETs.      

Cooperative Quantum Cutting in Yb $^{3+}$–Tb $^{3+}$ Codoped Borosilicate Glasses

Quantum cutting down-conversion (DC) with the emission of two near-infrared photons for each blue photon absorbed is realized in $hbox{Yb}^{3+}hbox{–}hbox{Tb}^{3+}$ codoped borosilicate glasses. With the excitation of $hbox{Tb}^{3+}$ ion by a 484-nm monochromatic light, emission from the $^{2} hbox{F} _{5/2}rightarrow ^{2} hbox{F} _{7/2}$ transition of $hbox{Yb}^{3+}$ ions is observed and this emission is proved to originate from the DC between $hbox{Tb}^{3+}$ ions and $hbox{Yb}^{3+}$ ions. Results shows that maximum quantum efficiency reach as high as 153%, which is comparable with that in oxyfluoride glass ceramics in this system. With the advantages of excellent transparence, easy shaping, good stability, and low cost, $hbox{Yb}^{3+}hbox{–}hbox{Tb}^{3+}$ codoped borosilicate glasses are potentially used as down-converter layer in silicon-based solar cells.      

Extraction of Density of States in Amorphous GaInZnO Thin-Film Transistors by Combining an Optical Charge Pumping and Capacitance–Voltage Characteristics

A technique for extracting the acceptorlike density of states (DOS) of $n$ -channel amorphous GaInZnO (a-GIZO) thin-film transistors based on the combination of subbandgap optical charge pumping and $C$– $V$ characteristics is proposed. While the energy level is scanned by the photon energy and the gate voltage sweep, its density is extracted from the optical response of $C$–$V$ characteristics. The extracted DOS shows the superposition of the exponential tail states and the Gaussian deep states ($N_{rm TA} = hbox{2} times hbox{10}^{18} hbox{eV}^{-1} cdot hbox{cm}^{-3}$, $N_{rm DA} = hbox{4} times hbox{10}^{15} hbox{eV}^{-1} cdot hbox{cm}^{-3}$, $kT_{rm TA} = hbox{0.085} hbox{eV}$, $kT_{rm DA} = hbox{0.5} hbox{eV}$ , $E_{O} = hbox{1} hbox{eV}$). The TCAD simulation results incorporated by the extracted DOS show good agreements with the measured transfer and output characteristics of a-GIZO thin-film transistors with a single set of process-controlled parameters.