New physical models, algorithms, and parameters are needed to accurately model emerging silicon-on-insulator (SOI) devices. The modeling approaches for various emerging SOI technologies are discussed in this paper.

In this work, we review our recent efforts to make effective use of atomistic calculations for the advancement of VLSI process simulation. We focus on three example applications: the behavior of implanted fluorine, arsenic diffusion and activation, and the impact of charge interactions on doping fluctuations.

Nowadays, silicon technologies with feature sizes around 100 nm are used in the microelectronics industry to produce gigabits integrated circuits. The prime part of numerical simulation in their development is now well established. One of the purpose of the numerical analyses is the improvement of the mechanical reliability. We synthetize in this paper various works we have performed on the macroscopical modeling and simulation of stress problems and their effects in silicon technologies.

In this work it is shown for the first time how to calculate in advance by momentum-based noise simulation for stationary Monte Carlo (MC) device simulations the CPU time, which is necessary to achieve a predefined error level. In addition, analytical expressions for the simulation-time factor of terminal current estimation are given. Without further improvements of the MC algorithm MC simulations of small terminal currents are found to be often prohibitively CPU intensive.

The radio-frequency thermal noise in fully-depleted (FD) silicon-on-insulator (SOI) MOSFETs and bulk MOSFETs is theoretically examined using a distributed-transmission-line model. It is shown that the thermal noise in a scaled-down SOI MOSFET is basically smaller than that in a scaled-down bulk MOSFET in a wide frequency range. In the radio-frequency range, parasitic resistances in source and drain don't yield a remarkable contribution to the difference in output thermal noise power between scaled-down bulk MOSFETs and scaled-down SOI MOSFETs. However, the output thermal noise of scaled-down SOI MOSFETs with a finite parasitic resistance is smaller than that of scaled-down bulk MOSFETs because of smaller channel capacitance.

This paper reviews the advantages of the silicon three-dimensional MMIC technology such as low loss transmission lines, high integration level, and high Q-factor on-chip inductors. Coupled to the masterslice concept, this technology also offers simple design procedure, short turn-around-time, low cost, and potential integration with LSI circuits. A K-band amplifier and an up-converter demonstrate the high frequency operation and low-power consumption benefits of the Si 3-D MMIC technology. A C-band Si-bipolar single-chip transceiver is proposed to illustrate the high integration level offered by the masterslice concept. Finally, the recent advances we achieved toward high Q-factor on-chip inductors provide the design of the S-band low noise amplifier presented in this paper.

This paper studies the anticontrol problem of making a continuous-time system chaotic by using impulsive control. The controller is designed to ensure the controlled orbit be bounded and, meanwhile, the controlled system have positive Lyapunov exponents, which are achieved near a stable limit cycle of the system. One illustrative example is given.

This paper addresses the fundamental challenges and possible solutions in designing and fabricating nanometer-scale CMOS transistor. Essential technology components such as advanced gate dielectrics, ultra-shallow junction, channel dopant profile engineering, and salicide are discussed. Ultra-scaled transistor with physical gate length down to 15 nm is demonstrated as a continued effort to push the traditional planar CMOS technology towards its physical limit.

A uniform raised-salicide technology has been investigated using both uniform selective-epitaxial-growth (SEG) silicon and salicide films, to reduce a junction leakage current of shallow source/drain (S/D) regions for high-performance CMOS devices. The uniform SEG-Si film without pits is formed by using a wet process, which is a carbon-free oxide removal only using a dilute hydrofluoric acid (DHF) dipping, prior to the Si-SEG process. After a titanium-salicide formation using a conventional two-step salicide process, this uniform SEG-Si film achieves good S/D junction characteristics. The uniform titanium-salicide film without bowing into a silicon is formed by a smaller Ti/SEG-Si thickness ratio, which results in a low sheet resistance of 5 Ω/sq. without a narrow-line effect. Furthermore, the drive current is maximized by this raised-salicide film using a Ti/SEG-Si thickness ratio of 1.0.

A practical method of measuring the contact resistance of a phosphorus-doped poly-Si plug formed on a lightly phosphorus-doped diffusion region in DRAM memory cells is described. Contact resistance was obtained electrically, using ordinary contact-chain test structures, by changing the measurement of the substrate bias. This separated the bias-dependent resistance of the lightly doped diffusion layer from the total resistance. The method was used experimentally to evaluate the feasibility of forming low-resistance contacts down to a diameter of 130 nm for giga-bit DRAMs. Electrical measurement showed that reducing the interface resistance between the poly-Si plug and the lightly doped diffusion layer was effective for forming low-resistance contacts, though a specific interface layer could not be detected by TEM observation.

Integration of spot-size converters (SSCs) with semiconductor optical amplifiers (SOAs) that improves chip-fiber optical coupling is inevitable for realizing high performance SOA modules. In this paper SSCs that can be easily integrated with SOAs and have little influence on the polarization sensitivity have been studied. We found that polarization insensitive active width-tapered SSCs can be realized by an optimum waveguide design of tensile-strained bulk structures. The SOA module exhibited large fiber-to-fiber gain (> 19 dB), small polarization sensitivity (< 0.4 dB), high fiber-coupled saturation output power (> +11.7 dBm) and record low module noise figure (< 6.3 dB) for the signal wavelength range of 1530-1560 nm.

We describe hybrid integration technologies that employ silica-based planar lightwave circuit (PLC) platforms, and report several high-performance optical components based on these technologies. First, we describe the requirements for optical integrated circuits. Then, we discuss the technologies used in hybrid integration, namely optical coupling between a semiconductor optical device and a silica waveguide, electrical signal transmission to the semiconductor optical device, and high quality optical signal processing. In addition, we describe optical integrated circuits developed for short- and long-haul networks. We realized these high-performance integrated components by combining appropriate hybrid integration technologies.

Various types of wavelength-selectable light sources (WSLs) and wavelength-tunable laser diodes (LDs) have been developed, and the one based on an array of distributed feedback (DFB) laser diodes (LDs) has the advantage of tuning that is both simple and stable tuning. It requires only the selection of a DFB-LD and a temperature control. We report on monolithically integrated WSLs with a DFB-LD array, multimode interference (MMI) coupler, semiconductor optical amplifier (SOA), and electro-absorption (EA) modulator. To make them compact, we introduced microarray structures and to ensure that they were easy to fabricate, we used selective area growth. For the WSL with an integrated EA modulator, we developed a center-temperature-shift method that optimizes the detuning wavelength between the lasing wavelength and the absorption edge wavelength of the EA-modulator. Using this method, we obtained a uniform extinction ratio and were able to demonstrate error-free 2.5-Gb/s transmission over a 600-km fiber span. A CW-WSL without an EA-modulator should provide enough output power to compensate the loss caused by the external modulators, but the high-power operation of a CW-WSL is sensitive to optical feedback from the front facet. We therefore used an angled facet in our WSLs and eliminated a mode hop problem. More than 20 mW of fiber-coupled power was obtained over 23 ITU-T channels on a 50-GHz grid.

We demonstrate a single high-order transverse mode surface emitting laser (VCSEL) with narrow trenches formed on a top surface. The design and the fabrication of a single high-order mode 850 nm GaAs VCSEL with micromachined surface relief are presented. Stable single-mode operation with a side-mode suppression ratio of over 40 dB was obtained in an entire measured current range. We obtained the maximum single mode power of over 3.5 mW and a record low series resistance of below 50 Ω. In addition, a single-lobe far field pattern is demonstrated even under high-order transverse mode operation by loading phase-shift on the top surface. A coupling efficiency with optical fibers is dramatically improved.

SQUID (Superconducting QUantum Interference Device) Photoscanning is an analytical technique intended for the noninvasive evaluation of semiconductor wafers and device structures. This method is based on the detection of the magnetic field of photocurrents locally induced in the sample under investigation by a focused laser beam. The magnetic field is monitored by means of a sensitive SQUID magnetometer while scanning the sample surface with the laser beam. Doping inhomogeneities in electronic grade silicon, grain boundaries in solar silicon, and defects in photovoltaic device structures have been analyzed.

A flash analog-to-digital converter (ADC) that uses resonant-tunneling complex gates is proposed. The ternary quantizers, consisting of monostable-to-multistable transition logic (MML) circuits, convert the analog input signal into the ternary thermometer code. This code is then converted into the binary Gray-code output by a multiple-valued multiple-input monostable-bistable transition logic element (M2-MOBILE). By assuming InP-based resonant-tunneling diode (RTD) and heterojunction field-effect transistor technology, we have carried out SPICE simulation that demonstrates a 4-bit, 10-GS/s ADC operation. The input bandwidth, defined as a frequency at which the effective number of bit decreases by 0.5 LSB, was also estimated to be 500 MHz. Compact circuit configuration, which is due to the combination of MML and M2-MOBILE, reduces the device count and power dissipation by a factor of two compared with previous RTD-based ADCs.

Phase-inversion between neighboring pulses appearing in carrier-suppressed return-to-zero pulses is effective in reducing the signal distortion due to chromatic dispersion and nonlinear effects. A generation method of the anti-phase pulses at 40 GHz is demonstrated by using semiconductor mode-locked lasers integrated with chirped gratings. Operation principle and pulse characteristics are described. Suppression of pulse distortion due to fiber dispersion is confirmed for generated anti-phase pulses. Repeaterless 150-km dispersion-shifted-fiber L-band transmission at 42.7 Gbit/s is demonstrated by using the pulse source.

This paper describes the recent progress made in developing wavelength tunable semiconductor light sources for WDM applications. Wide and quasi-continuous wavelength tunings were investigated for a wavelength-selectable laser and a wavelength tunable distributed Bragg reflector (DBR) laser having a super structure grating (SSG). A wavelength-selectable laser consisting of a DFB laser array, a multi-mode interferometer (MMI), and a semiconductor optical amplifier (SOA) demonstrated a quasi-continuous tuning range of 46.9 nm by using temperature control. A wavelength-tunable DBR laser with SSG exhibited a quasi-continuous tuning range of 62.4 nm by using three tuning current controls. Wavelength stabilization was also demonstrated under the temperature variations of 5.

We have demonstrated active mode hopping suppression in external-cavity semiconductor lasers including a diffraction grating as a wavelength-selecting device. The feedback control nullifies the difference between the oscillation wavelength and selected wavelength based on observed changes in diffraction angle. The control has suppressed mode hopping over a 7.5 times wider span than without control. And when combined with conventional mode hopping suppression techniques, mode-hop-free oscillation is achieved over 130 nm. Our approach can be used for most Littman-type external-cavity semiconductor lasers with simple attachments; it will be useful for continuous wavelength sweeping and for long-term wavelength stabilization.

Breakthroughs in crystal growth and conductivity control of nitride semiconductors during last two decades have led to such developments as high-brightness blue and green light-emitting diodes and long-lived violet laser diodes and so on. All of these nitride-based devices are robust and the most environmentally-friendly ones available. They enable us to save tremendous amount of energy and will be key devices in advanced information technology. Further progress in the area of crystal growth and device engineering will open up new frontier devices based on nitride semiconductors. In this paper, the evolution of nitride-based light-emitting devices is reviewed and the key issues, which must be addressed for nitrides to be fully developed, are discussed.