Effective Modulation of Quadratic Voltage Coefficient of Capacitance in MIM Capacitors Using $hbox{Sm}_{2}hbox{O}_{3}/hbox{SiO}_{2}$ Dielectric Stack

We report the first demonstration of metal–insulator–metal (MIM) capacitors with $hbox{Sm}_{2}hbox{O}_{3}/hbox{SiO}_{2}$ stacked dielectrics for precision analog circuit applications. By using the “canceling effect” of the positive quadratic voltage coefficient of capacitance (VCC) of $hbox{Sm}_{2}hbox{O}_{3}$ and the negative quadratic VCC of $hbox{SiO}_{2}$, MIM capacitors with capacitance density exceeding 7.3 $hbox{fF}/muhbox{m}^{2}$ , quadratic VCC of around $-hbox{50} hbox{ppm/V}^{2}$ , and leakage current density of $hbox{1} times hbox{10}^{-7} hbox{A/cm}^{2}$ at $+$3.3 V are successfully demonstrated. The obtained capacitance density and quadratic VCC satisfy the technical requirements specified in the International Technology Roadmap for Semiconductors through the year 2013 for MIM capacitors to be used in precision analog circuit applications.      

Investigation on the Electric Properties of $ hbox{Bi}_{1.5}hbox{ZnNb}_{1.5}hbox{O}_{7}$ Thin Films Grown on TiN Substrate for MIM Capacitors

A small crystalline phase was formed in the Bi_1.5ZnNb_1.5O₇ (BZN) film grown at 300degC on TiN/SiO₂/Si substrate using RF-magnetron sputtering. A 46-nm-thick BZN film exhibited a high capacitance density of 13.6 fF/mum² at 100 kHz with a dielectric constant of 71, which did not change even in the gigahertz range (1-6 GHz). The quality factor was high, approximately 50, at 2.5 GHz. The leakage-current density was low, approximately 5.66 nA/cm², at 2 V. The quadratic voltage and temperature coefficients of capacitance were approximately 631 ppm/V² and 149 ppm/degC at 100 kHz, respectively. These results indicate that the BZN film grown on TiN substrate at 300degC can be a good candidate material for metal-insulator- metal capacitors.     

High Density and Low Leakage Current in $ hbox{TiO}_{2}$ MIM Capacitors Processed at 300 $^{circ} hbox{C}$

We report Ir/TiO₂/TaN metal-insulator-metal capacitors processed at only 300degC, which show a capacitance density of 28 fF/mum² and a leakage current of 3 times 10^-8 (25degC) or 6 times 10^-7 (125degC) A/cm² at -1 V. This performance is due to the combined effects of 300degC nanocrystallized high-kappa TiO₂, a high conduction band offset, and high work-function upper electrode. These devices show potential for integration in future very-large-scale-integration technologies.     

A high performance MIM capacitor using HfO2 dielectrics

Metal-insulator-metal (MIM) capacitors with a 56 nm thick HfO₂ high-κ dielectric film have been fabricated and demonstrated for the first of time with a low thermal budget (~200°C). Voltage linearity, temperature coefficients of capacitance, and electrical properties are all characterized. The results show that the HfO₂ MIM capacitor can provide a higher capacitance density than Si₃N₄ MIM capacitor while still maintaining comparable voltage and temperature coefficients of capacitance. In addition, a low leakage current of 2×10^-9 A/cm² at 3 V is achieved. All of these make the HfO ₂ MIM capacitor to be very suitable for use in silicon RF and mixed signal IC applications     

High-Performance Metal–Insulator–Metal Capacitors Using Amorphous BaSm2Ti4O12 Thin Film

The dielectric properties of the amorphous BaSm₂Ti₄O₁₂ (BSmT) film with various thicknesses were investigated to evaluate its potential use as a metal-insulator-metal (MIM) capacitor. An amorphous 35-nm-thick BSmT film grown at 300 degC exhibited a high capacitance density of 9.9 fF/mum² at 100 kHz and a low leakage current density of 1.790 nA/cm² at 1 V. The quadratic and linear voltage coefficients of capacitance of the film were 599 ppm/V² and -81 ppm/V at 100 kHz, respectively. The temperature coefficient of capacitance of the film was also low about 236 ppm/degC at 100 kHz. These results confirmed the suitability of the amorphous BSmT film as a high-performance MIM capacitor     

Fabrication of Self-Aligned Enhancement-Mode $ hbox{In}_{0.53}hbox{Ga}_{0.47}hbox{As}$ MOSFETs With $ hbox{TaN/HfO}_{2}hbox{/AlN}$ Gate Stack

In this letter, we report the fabrication and characterization of self-aligned inversion-type enhancement-mode In_0.53Ga_0.47As metal-oxide-semiconductor field-effect transistors (MOSFETs). The In_0.53Ga_0.47As surface was passivated by atomic layer deposition of a 2.5-nm-thick AIN interfacial layer. In_0.53Ga_0.47As MOS capacitors showed an excellent frequency dispersion behavior. A maximum drive current of 18.5 muA/mum was obtained at a gate overdrive of 2 V for a MOSFET device with a gate length of 20 mum. An I_on/_off ratio of 104, a positive threshold voltage of 0.15 V, and a subthreshold slope of ~165 mV/dec were extracted from the transfer characteristics. The interface-trap density is estimated to be ~7-8 times 10¹² cm^-2 ldr eV^-1 from the subthreshold characteristics of the MOSFET.     

High-density MIM capacitors using Al2O3 andAlTiOx dielectrics

We have investigated the electrical characteristics of Al₂ O₃ and AlTiO_x MIM capacitors from the IF (100 KHz) to RF (20 GHz) frequency range. Record high capacitance density of 0.5 and 1.0 μF/cm² are obtained for Al₂ O₃ and AlTiO_x MIM capacitors, respectively, and the fabrication process is compatible to existing VLSI backend integration. However, the AlTiO_x MIM capacitor has very large capacitance reduction at increasing frequencies. In contrast, good device integrity has been obtained for the Al₂O₃ MIM capacitor as evidenced from the small frequency dependence, low leakage current, good reliability, small temperature coefficient, and low loss tangent     

Achieving Low-$V_{T}$ Ni-FUSI CMOS by Ultra-Thin $hbox{Dy}_{2}hbox{O}_{3}$ Capping of Hafnium Silicate Dielectrics

This letter reports that the effective work function (eWF) of Ni-Fully Silicided (Ni-FUSI) devices with HfSiON gate dielectrics can be modulated toward the silicon conduction band-edge by deposition of an ultra-thin Dy₂O₃ cap layer on the host dielectric. The obtained eWF depends on the deposited cap layer thickness and the Ni-FUSI phase, with 10 Aring Dy₂O₃ cap resulting in DeltaeWF ap 400 meV and final eWF ap 4.08 eV for NiSi-FUSI. Dielectric intermixing occurs without impacting the VT uniformity, gate leakage, mobility, and reliability. Well-behaved short-channel devices ( Lg ~ 100 nm, SS ~ 70 mV/dec, and DIBL ~ 65 mV/V) are demonstrated for both HfSiON and [HfSiON/Dy₂O₃ cap (5 Aring)] devices with NiSi-FUSI gates, corresponding to a similar . This capping approach, when combined with Ni-silicide FUSI phase engineering, allows (n-p) values up to 800 meV, making it promising for low- CMOS.     

Reliable Low-Cost Fabrication of Low-Loss $hbox{Al}_{2}hbox{O} _{3}{:}hbox{Er}^{3+}$ Waveguides With 5.4-dB Optical Gain

A reliable and reproducible deposition process for the fabrication of Al₂O₃ waveguides with losses as low as 0.1 dB/cm has been developed. The thin films are grown at ~ 5 nm/min deposition rate and exhibit excellent thickness uniformity within 1% over 50times50 mm² area and no detectable OH^- incorporation. For applications of the Al₂O₃ films in compact, integrated optical devices, a high-quality channel waveguide fabrication process is utilized. Planar and channel propagation losses as low as 0.1 and 0.2 dB/cm, respectively, are demonstrated. For the development of active integrated optical functions, the implementation of rare-earth-ion doping is investigated by cosputtering of erbium during the Al₂O₃ layer growth. Dopant levels between 0.2-5times10²⁰ cm^-3 are studied. At Er³⁺ concentrations of interest for optical amplification, a lifetime of the ⁴I_13/2 level as long as 7 ms is measured. Gain measurements over 6.4-cm propagation length in a 700-nm-thick Al₂O₃:Er³⁺ channel waveguide result in net optical gain over a 41-nm-wide wavelength range between 1526-1567 nm with a maximum of 5.4 dB at 1533 nm.     

Room-Temperature Deposited Titanium Silicate Thin Films for MIM Capacitor Applications

High-k titanium silicate (i.e., TiSiO₄) thin films of various thicknesses (in the 4.5- to 160-nm range) were successfully deposited by means of a sputter deposition process at room-temperature and integrated into metal-insulator-metal (MIM) capacitors. It is shown that the TiSiO₄-based capacitors can exhibit a capacitance density as high as 30 fF/mum² while maintaining low dielectric dispersion and losses. An excellent voltage linearity was also obtained ( alpha~600 ppm/V² at 8.2 fF/mum²) together with a high dielectric constant of 16.5 and low leakage current of about 10 nA/cm² at 1 MV/cm. Our results thus show that TiSiO₄ films constitute a very promising approach for the achievement of high performance MIM capacitors     

$hbox{In}_{0.53}hbox{Ga}_{0.47}hbox{As}$ Channel MOSFETs With Self-Aligned InAs Source/Drain Formed by MEE Regrowth

Abstract-We report Al₂O₃Zln_0.53Ga_0.47As MOSFETs having both self-aligned in situ Mo source/drain ohmic contacts and self-aligned InAs source/drain n⁺ regions formed by MBE regrowth. The device epitaxial dimensions are small, as is required for 22-nm gate length MOSFETs; a 5-nm In_0.53Ga_0.47As channel with an In_0.4sAl_0.52As back confinement layer and the n⁺⁺ source/drain junctions do not extend below the 5-nm channel. A device with 200-nm gate length showed I_D = 0.95 mA/mum current density at V_GS = 4.0 V and g_m = 0.45 mS/mum peak transconductance at V_DS = 2.0 V.     

Effects of Oxynitride Buffer Layer on the Electrical Characteristics of Poly-Silicon TFTs Using $hbox{Pr}_{2}hbox{O}_{3}$ Gate Dielectric

In this paper, we have developed high-k Pr₂O₃ poly-Si thin-film transistors (TFTs) using different N₂O plasma power treatments. High-k Pr₂O₃ poly-Si TFT devices using a 200-W plasma power exhibited better electrical characteristics in terms of high effective carrier mobility, high driving current, small subthreshold slope, and high I_ON/I_OFF current ratio. This result is attributed to the smooth Pr₂O₃/poly-Si interface and low interface trap density. Pr₂O₃ poly-Si TFT with a 200-W N₂O plasma power also enhanced electrical reliabilities such as hot carrier and positive bias temperature instability. All of these results suggest that a high-k Pr₂O₃ gate dielectric with the oxynitride buffer layer is a good candidate for high-performance low-temperature poly-Si TFTs.     

AlGaN/GaN MOS-HEMT With $hbox{HfO}_{2}$ Dielectric and $hbox{Al}_{2}hbox{O}_{3}$ Interfacial Passivation Layer Grown by Atomic Layer Deposition

We have developed a novel AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistor using a stack gate HfO₂/Al₂O₃ structure grown by atomic layer deposition. The stack gate consists of a thin HfO₂ (30-A) gate dielectric and a thin Al₂O₃ (20- A) interfacial passivation layer (IPL). For the 50-A stack gate, no measurable C-V hysteresis and a smaller threshold voltage shift were observed, indicating that a high-quality interface can be achieved using a Al₂O₃ IPL on an AlGaN substrate. Good surface passivation effects of the Al₂O₃ IPL have also been confirmed by pulsed gate measurements. Devices with 1- mum gate lengths exhibit a cutoff frequency (fT) of 12 GHz and a maximum frequency of oscillation (f _MAX) of 34 GHz, as well as a maximum drain current of 800 mA/mm and a peak transconductance of 150 mS/mm, whereas the gate leakage current is at least six orders of magnitude lower than that of the reference high-electron mobility transistors at a positive gate bias.     

Yttrium oxide/silicon dioxide: a new dielectric structure forVLSI/ULSI circuits

Electrical characteristics of Al/yttrium oxide (~260 Å)/silicon dioxide (~40 Å)/Si and Al/yttrium oxide (~260 Å)/Si structures are described. The Al/Y₂O₃/SiO₂/Si (MYOS) and Al/Y₂ O₃/Si (MYS) capacitors show very well-behaved I-V characteristics with leakage current density <10^-10 A/cm² at 5 V. High-frequency C- V and quasistatic C-V characteristics show very little hysteresis for bias ramp rate ranging from 10 to 100 mV/s. The average interface charge density (Q_f+Q _it) is ~6×10¹¹/cm² and interface state density D_it is ~10¹¹ cm^-2-eV^-1 near the middle of the bandgap of silicon. The accumulation capacitance of this dielectric does not show an appreciable frequency dependence for frequencies varying from 10 kHz to 10 MHz. These electrical characteristics and dielectric constant of ~17-20 for yttrium oxide on SiO₂/Si make it a variable dielectric for DRAM storage capacitors and for decoupling capacitors for on-chip and off-chip applications     

Characterizing Fluorine-Ion Implant Effects on Poly-Si Thin-Film Transistors With ${hbox{Pr}}_{2}{hbox{O}}_{3}$ Gate Dielectric

The fluorine ion implantation applied to the polycrystalline silicon thin-film transistors (poly-Si TFTs) with high-k Pr₂O₃ as gate dielectric is investigated for the first time. Using the Pr₂O₃ gate dielectric can obtain a high gate capacitance density and thin equivalent-oxide thickness, exhibiting a greatly enhancement in the driving capability of TFT device. Introducing fluorine ions into the poly-Si film by fluorine ion implantation technique can effectively passivate the trap states in the poly-Si film and at the Pr₂O₃/poly-Si interface to improve the device electrical properties. The Pr₂O₃ TFTs fabricated on fluorine-implanted poly-Si film exhibit significantly improved electrical performances, including lower threshold voltage, steeper subthreshold swing, higher field-effect mobility, lower off-state leakage current, and higher on/off current ratio, as compared with the control poly-Si Pr₂O₃ TFTs. Also, the incorporation of fluorine ions also improves the reliability of poly-Si Pr₂O₃ TFTs against hot-carrier stressing, which is attributed to the formation of stronger Si-F bonds. Furthermore, superior threshold-voltage rolloff characteristic is also demonstrated in the fluorine-implanted poly-Si Pr₂O₃ TFTs. Therefore, the proposed scheme is a promising technology for high-performance and high-reliability solid-phase crystallized poly-Si TFT.     

Electrical Properties of Low-$V_{T}$ Metal-Gated n-MOSFETs Using $hbox{La}_{2}hbox{O}_{3}/hbox{SiO}_{x}$ as Interfacial Layer Between HfLaO High- $kappa$ Dielectrics and Si Channel

In this letter, we report that by employing the La₂O₃/SiO_x interfacial layer between HfLaO (La = 10%) high- and Si channel, the Ta₂C metal-gated n-MOSFETs V_T can be significantly reduced by ~350 mV to 0.2 V, satisfying the low-Vy device requirement. The resultant n-MOSFETs also exhibit an ultrathin equivalent oxide thickness (~1.18 nm) with a low gate leakage (J_G = 10 mA/cm² at 1.1 V), good drive performance (I_on = 900 muA/mum at I_soff = 70 nA/mum), and acceptable positive-bias-temperature-instability reliability.     

High-Performance MIM Capacitors Using HfLaO-Based Dielectrics

Metal-insulator-metal (MIM) capacitors fabricated with (8%) La-doped HfO₂ single layer as well as HfLaO/ LaAlO₃/HfLaO multilayer dielectric stack are demonstrated. While the La-doped HfO₂ single layer is crystallized at 420^°C annealing, HfLaO/LaAlO₃/HfLaO multilayer dielectric stack remains amorphous. A high dielectric-constant value of 38 can be obtained when 8% La-doped HfO₂ is crystallized into cubiclike structure. However, it is observed that the linearity of MIM capacitor is degraded upon crystallization. The multilayer film has lower average dielectric constant but shows low quadratic voltage linearity of less than 1000 ppm/V² up to a capacitance density of 9 fF/?m² . It is observed that the HfLaO single-layer MIM is suitable for the applications with requirements of high capacitance density and robust reliability, while the multilayer MIM is suitable for a precision circuit.     

Improvement of the Performance of TiHfO MIM Capacitors by Using a Dual Plasma Treatment of the Lower Electrode

We show that a conventional nitrogen plasma treatment is insufficient to suppress the formation of an interfacial layer at the bottom electrode of TiHfO metal-insulator-metal (MIM) capacitors. However, the capacitance density and leakage current of TaN/TiHfO/TaN MIM capacitors monotonically improve by exposing the lower TaN electrode to an additional oxygen plasma treatment. By performing dual oxygen and nitrogen plasma treatments on the lower electrode, the leakage current was 4.8 times 10^-6 A/cm² (at -1 V) at a 28 fF/ mum² capacitance density.     

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.      

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.